Blame it on a marketing survey. In 2001, the England and Wales Cricket Board commissioned the biggest piece of market research in the game’s history. They were told cricket was ‘socially inaccessible’, and that there existed a vast swath of ‘cricket tolerators’ — those who didn’t hate the game yet didn’t attend matches. So the ECB decided to take cricket to them. Twenty20, which could be crammed in after work on a midsummer’s evening, was created in the summer of 2003.

The new game followed a traditional path: born in England, but perfected abroad. After India overcame its initial opposition, the country inexorably became the home of T20. A decade ago the Indian Premier League, the nation’s T20 domestic league, was launched, with matches at 8 p.m. every day, like an Indian soap opera. This was less a traditional sports league than an alliance between cricket and Bollywood, which provided many of the owners. Cricket, everyone knew, would never be the same again.

Ten years on, I visited India for this year’s IPL season. What I saw was a game that, far from being infantilised, is being taken more seriously. Broadcasters once focused so much on the cheerleaders and the Bollywood actors in the crowd that it was sometimes easy to forget you were actually watching cricket; now, more analytical commentary has been introduced to dissect complex strategies. Many coaches and players consider T20 more strategic than Test cricket, because there isn’t any time to recover from a mistake; they also report, sadly, that the IPL’s incessant parties have given way to professionalism. Bangalore have even ditched their cheerleaders: T20 no longer needs sex to sell it. The cricket itself does the job nicely.

Like any new industry expanding at a dizzying pace, T20’s surge brought multifarious unforeseen problems. Club vs country rows have destroyed the West Indies, whose stars have shunned international cricket because they can earn far more playing in the IPL and other T20 leagues. There have been myriad corruption scandals and the sport has never been so vulnerable to doping. But such challenges should not obscure T20’s great achievements. The format has democratised and popularised cricket: shifts that all cricket lovers should savour.

The IPL gave cricket its equivalent of the football Premier League: a domestic league that is really an international one. Unlike traditional international cricket, it doesn’t care about hierarchies or status. Only cricketers from 12 countries are allowed to play Test matches; the IPL is a democracy in which everyone is welcome. T20 has created a global free market for talent. This year’s IPL included four Afghans; three are teenagers. It also featured 17-year-old Sandeep Lamichhane, the first-ever Nepalese player in a major league. ‘Not just me, but the entire nation is proud of you,’ Nepal’s prime minister said after Lamichhane signed for Delhi.

T20 has made cricket a sport for those from Kabul and Kathmandu, not just Kent and Kolkata. And players are paid according to what they are worth, not the nationality on their passport. In international cricket, Afghanistan’s Rashid Khan earns 3 per cent as much as England’s Test captain Joe Root. In this year’s IPL, Rashid earned £1 million; Root was not picked up at all.

Don’t just call the cash vulgar. It has led Indian grounds to treat fans with new respect (transforming toilet facilities, for instance), funded proper pensions for retired cricketers and officials, and allowed more cash to be invested in grassroots facilities. T20 money has also turbocharged overdue innovations in cricket — including global scouting networks which scour leagues in Afghanistan and beyond in search of previously neglected talent. Some decry all this as not cricket — and, to be sure, the skills are distinct from the Test game. Yet T20’s best batsman is probably South Africa’s A.B. de Villiers, underpinned by a technique that also made him a wondrous Test player. The best bowlers are not stodgy medium pacers but the fastest bowlers or the best spinners. Indeed, one of the greatest joys of T20 has been how it has revived cricket’s most capricious art — legspin bowling. The top five T20 bowlers today are all legspinners.

The world over, T20 is helping the sport ditch its old rigid hierarchies. There are thriving leagues from Hong Kong to the Caribbean, where T20 has led to a resurgence in the West Indies, the reigning world champions. In England, T20 means county cricket is better supported than at any time in the past 50 years; without the income from the T20 blast, indeed, some of the 18 first-class counties would probably have gone bankrupt. And T20 has helped women’s cricket surge, driving the introduction of professionalism in the past five years. When a women’s IPL is eventually introduced, the best female players worldwide will finally be paid what they are worth.

What this all means for Test cricket, of course, is still not entirely clear, especially with even shorter formats, such as England’s new 100-ball concept, proliferating. But T20 did not create Test cricket’s problems. In England, Test crowds have never been more buoyant; it was easier to get a seat at Botham’s Ashes in 1981 — just look at the grainy YouTube footage — than for this summer’s Tests against India. T20 supporters have not replaced Test fans; instead, they have expanded cricket’s overall support base. And many love both: after England collapsed to lose the opening Test of the summer before lunch on the fourth day, thousands stayed on at Lord’s, taking solace by watching the IPL final on big screens.

There are signs that competition from T20 is making Test cricket itself better. In the past three years, Tests have finally embraced day-night matches, taking the revolutionary approach that sport should be played when people can actually watch; expanded to allow Afghanistan and Ireland to play; and introduced a championship with a play-off final. Rather than killing Test cricket, T20 could yet be the upstart that forces its big brother out of stagnation.