Some years ago, not long after I joined The Daily Telegraph, I started writing a sitcom set in a regional theatre – enthralled by a world I had barely known before. The crumbling playhouse and the tired civic arts centre offered a rich panoply of characters and a scenario of entertaining struggle: warring egos, funding crises, and so on.

Drafts languish at the bottom of a drawer. Work, and a young family, intervened. But so did reality: after more than a decade in the doldrums, regional theatre entered a new golden age, assisted by a boost in funding. The comic stereotype of benighted thespian endeavour – as portrayed by Ian McKellen and Anthony Hopkins on BBC Two on Saturday in Ronald Harwood’s The Dresser – no longer held.

Might the stereotype be back, though? On the face of it, judging by box office figures for 2014 – released yesterday by UK Theatre, which represents most theatres outside the West End – the good news story is still rolling on. Despite the challenges presented by Arts Council cuts and the squeeze on local authority budgets, business is apparently booming.

Audiences are up and punters are seemingly prepared to pay more: the average price paid for each ticket rose by 5.5 per cent, significantly higher then inflation. Box-office takings outside London increased by 8 per cent.

Look at the figures more closely, though, and things aren’t as rosy. As the report states: “2014 was the year of the big family musical, which took almost £1 in every £4 taken at the box office”. So the lavish family treat is doing fine – the touring incarnations of Wicked, The Lion King and so on. But while I can’t denigrate those shows, what about more challenging fare? Musicals for adults saw a slump in activity (23 per cent fewer tickets sold), while demand for plays was down 7 per cent.

The regions should be powering the revival of our national theatre, not just feeding off its more populist cast-offs

The facts tell a discomforting story: tried-and-tested, safe entertainment is gaining ground. Work that is supposed to be a staple ingredient of the culture – the new writing, the revivals – is getting edged out.

Those who admit to problems paint a picture of a decline in serious play-watching. Max Stafford-Clark, artistic director of touring company Out of Joint, despairs at the poor attendance for a well-reviewed play inspired by the coming-out of former Welsh rugby captain Gareth Thomas – Crouch, Touch, Pause, Engage. “The mid-scale tour has become increasingly economically unviable,” he warned.

Danny Lee Wynter and Belinda Lang in The Glass Menagerie at Nuffield Theatre in Southampton

I saw how perilous those economics are recently, reviewing two revivals of Tennessee Williams’s The Glass Menagerie, one in Southampton, the other in Liverpool. The audience was thin on the ground. Going to a half-empty playhouse is a dispiriting experience. Whereas success can breed success – witness the trade Jonathan Church has engineered at Chichester, combining family-friendly shows with more experimental fare and serious-minded drama – those theatres that don’t have the means, and/or lack the nous to get the balance right could fall off the cliff.

What is to be done? The first thing is to concede that although regional theatre and the West End collectively offer an amazing success-story, we can’t simply lump them together, and the differences between them could become a permanent rift as the lion’s share of subsidy, ability and activity remains in London. The regions should be powering the revival of our national theatre, not just feeding off its more populist cast-offs. Half of me would dust down that sitcom and fit it to these penny-pinched times. The better half, which marvels at the potential of theatre outside London, would rather the sector was made more secure and certain of its future.

That means more funding, more proactive emphasis on straight drama, less complacency. The report offers many reasons to rejoice. It also acts as a wake-up call.