When it comes to keeping it real, Ken Loach is in a league of his own. For more than five decades, he has carried the torch for British social realism; that fine tradition of everyday, usually working-class drama that has produced some of the most powerful, important cinema of our times. But 83-year-old Loach is practically the last man standing. He is like the David Attenborough of British cinema: when he goes, what will happen?

Loach already announced his retirement in 2014, before returning to make I, Daniel Blake. Now he is back with Sorry We Missed You, which tallies the toll of the gig economy on a hard-up Newcastle upon Tyne family. Promises of “being your own boss” come with ruthless terms and conditions for delivery driver Ricky, while his care-worker wife contends with exploitative employers, difficult patients and long bus journeys. It is another clear-eyed take on Broken Britain. Had there been more films like it, we might have a better idea of how we got to where we are now.

Looking back, social realism has often functioned as a stepping stone for British film-makers. Having made an impression with hard-hitting, state-of-the-nation dramas, they are often tempted by bigger things. That is what happened with most of Loach’s 1960s contemporaries. Directors such as John Schlesinger, Tony Richardson and Karel Reisz all went off to Hollywood. Similarly, latter-day successors such as Andrea Arnold (Fish Tank) and Lynne Ramsay (Morvern Callar) have worked in the US on the likes of American Honey and You Were Never Really Here. Even Mike Leigh, once a dependable fixture like Loach, has spent the past decade making historical dramas (Mr Turner, Peterloo). Shane Meadows is a worthy Loach successor, but he has recently only operated on the small screen (This Is England, The Virtues).

Social realism has become a bit of an unsexy genre at the cinema, squeezed out at the box office by more escapist fare, and often tinged with a sort of old-fashioned didacticism. Loach has often been accused of that. There is also the uncomfortable feeling that Loach’s stories of bottom-rung strife are primarily consumed by middle-class cinephiles. They feel guilty for watching, but guiltier for not watching.

Loach’s plain-spoken delivery method doesn’t have to be the only option. Witness more lyrical recent British films such as God’s Own Country, Ray & Liz, The Levelling or Bait – all of which gave us the up-to-the-minute “social” without so much of the “realism”. Then again, I, Daniel Blake was a triumph: it took the top prize at Cannes and gave Loach the biggest box-office hit of his career. It also sparked debate in parliament and elsewhere. If Sorry We Missed You does the same, perhaps the genre is due a revival. But if Loach leaves without a successor, we’ll be sorry.