There was a moment during the first half of last season when Lucas Pérez was asked what his parents made of the form that saw him closing in on a goalscoring record at Deportivo, held by the Brazilian striker Bebeto. “They’re just happy to have me around,” he replied. He had been away since he was a teenager and spent the previous four years in Greece and Ukraine, the final months there the “worst of my life”, but at last he was home. Now less than a year later, he has gone again.

Arsenal made an offer too good to refuse, however much Pérez had missed Galicia: a big club, Champions League football, the chance to compete for titles, treble the salary, and a transfer fee that Deportivo not only needed but welcomed and that met his buy-out clause: €20m, £17m. London is not Lviv, either. As for Arsenal, they got a quick, skilful, mobile forward who might not be a starter, nor have been their initial target, but who scored 17 times in La Liga and has been directly involved in more goals than any Spaniard since the start of last season.

Just ahead of Pérez in the goalscoring charts last season was Eibar’s Borja Bastón, on 18. He signed for Swansea City for £15m, where he joins Fernando Llorente, signed from Sevilla. They are part of a significant exodus from Spain to the Premier League this summer: Manquillo, Nolito, Bravo, Feghouli, Bailly, Negredo … the list goes on. When Shkodran Mustafi left Valencia on Tuesday night to join Pérez at Arsenal, it brought the number of players who have made the move to 17, and Vicente Iborra, Ignacio Camacho and Aymen Abdennour may yet join them. West Bromwich Albion have offered €18m for the Málaga midfielder, Sunderland’s €9m bid for Iborra was rejected by Sevilla and Chelsea are in talks over taking the defender Abdennour on loan from Valencia.

Spaniards moving to England is nothing new but this is a little different, a pattern that was already present yet has become more apparent and is illustrated by Pérez’s move.

For the best players at Spain’s “other” clubs keen to compete and to secure a contract more in keeping with their talent, a clear choice emerged some time ago: join Real Madrid or Barcelona (or, later, Atlético Madrid) or go abroad, where the financial and footballing muscle was greater. England offered opportunities that would otherwise have been denied to players such as David Silva or Juan Mata.

But of this summer’s signings, perhaps only Nolito fits that pattern; while each case is different, the rest come largely from a second tier of footballers. This time, the very best of La Liga have remained in Spain: Real Madrid and Barcelona still have Messi, Ronaldo, Bale and Suárez, while Atlético kept hold of Antoine Griezmann and Kevin Gameiro left Sevilla to join him at the Vicente Calderón. It is the “others” who have departed. This is not just a different generation; it is a different level. Attractive, but for other reasons.

English clubs, even beyond the Premier League, see in Spain a market that offers a reasonable price-quality relationship, a place for the risk-averse to sign a ready-made solution. It is a market in which they have confidence, one that has produced talented players, where development is good, and whose clubs have performed well in Europe, and is still cheaper than the Premier League.

Yet that risk-averse element may be innately risky; it may mean they are missing out on the best buys for players who will not raise the level dramatically. There is a habit of overlooking younger, “unproven” talent: everyone wants Griezmann now, no one wanted him enough to pay €30m two years ago; Sandro went to Málaga for free, not England; and the queue at Álvaro Morata’s door was not there two years ago. Instead, they favour players who offer a “guaranteed” return. How much of a return is another issue; a “return” no longer means signing a potential star, necessarily. It is not about Paul Pogba, it is about the men who cost a quarter of his fee.

Spain becomes a trusted testing ground for clubs who know that even if a player’s value rises, they can still meet it. There is the story of a manager telling his club to sign a young midfielder, insisting that he will be worth €100m in two years. To which he is told: “Let’s sign him in two years, then.” The example comes from the very highest level and from Spain, from clubs who know they can get their man, but there is an element of that when it comes to all clubs with money and right now English clubs have money – especially compared to Spanish ones.

“I know English clubs that work very hard when it comes to scouting but all the information that they gather they then don’t use it when it finally comes to making signings,” admits the Sevilla sporting director, Monchi. “Why? Because they have money. The attitude is: I’m not going to discover [Seydou] Keita at Lens I’m going to let Sevilla do that and then buy Keita from Sevilla. The money allows English clubs to not take the risk.”

This summer that process has continued; more importantly, it has continued down the market and down the league; it does not just apply to obvious targets signed as a team’s stand-out star, whose numbers on the market get fewer.

Eric Bailly, in action here for Manchester United against Hull City, moved to Old Trafford from Villarreal. Photograph: Matt West/BPI/Rex/Shutterstock

The existence of buy-out clauses at Spanish clubs also helps to facilitate the move: a fee is set at which clubs know they can get their player fight-free and at which the seller can present it to fans as a victory of sorts, or at least a move about which they could do nothing. The clause is usually set a little high, but no longer so high as to be prohibitive. For players and their agents, it removes some of the potential battle to find a way out, making life easier for everyone. Put in very simplistic terms: these are players who are available.

“Why are English teams turning to Spain?” asks one representative involved in deals between the two countries. “Money, basically. They think they’re getting a top striker for half price and the salary will be half.”

Which is still a lot for Spain, and that is important too. Spanish clubs see in England a cash-rich market they need to sell to, one where they can get big fees for their players. Fuera de mercado, as they say: beyond the market value. A place where every club is rich and even the second division can pay fees that clubs in Spain’s primera division cannot. The Premier League is a threat to La Liga but it has also proven vital to its financial health.

“It is a very good market for us; we sell a lot of players there,” admits Monchi, despite the fact that, this summer, his club has not followed the trend, with Gameiro (Spain), Krychowiak (France), Banega (Italy) and Coke (Germany) all departing for different destinations. One agent is rather more blunt: “Frankly, when they see an English club coming, Spanish sporting directors rub their hands together in glee,” he says. “When the call comes they think of a fee that’s ridiculous and quote that.”

The Premier League has certainly been lucrative for Spanish clubs. £17m for Pérez and £15m for Bastón appears to be a lot of money. But it may be time to recalibrate what counts as “too much” as the income from the new £7bn TV deal reaches Premier League clubs. They pay that because they can. This looks like a sellers’ market to the Spanish and like a buyers’ market to the English. Spanish players may have seemed overpriced this summer, but the context is a window in which Christian Benteke set Crystal Palace back £27m and Yannick Bolaise cost £25m.