Tate stresses its departing director has ‘diversified’ the collection, but it has hidden its treasures and let its galleries slide into insulting incoherence – and visitors have voted with their absence

In the last nine years Tate has had some hits, but its misses have become embarrassing. Tate Modern’s Turbine Hall is currently occupied by a feeble installation that would be weak in an ordinary-sized art space, let alone this gigantic one. It’s become genuinely hard to understand what Tate’s priorities are when it chooses artists for the annual Turbine Hall commission. And the Turner prize is even more mystifying. Once the stage of shocking, provocative art that engaged – whether they were for or against – a massive public, it has retreated into wilful obscurity, its trips around the UK starting to seem part of a studied wholesomeness. What’s the point of staging it in Bradford when the shortlist just exports the enigmatic tastes of a metropolitan elite?

Is Maria Balshaw, who is quitting her post as director of Tate , solely responsible for this? No, but perhaps she is courageously taking the blame and allowing the institution to reinvent itself as it needs to, fast. The achievements Tate stresses in its announcement of her departure centre on how she has “diversified” the collection, exhibition and audiences. But in that noble quest, there has been a loss of artistic ambition, aesthetic thrills, raw horror and beauty. Sometimes we really do want art for art’s sake and Tate has lost sight of that.