"My understanding is that a few years ago, if we knew the degree of interpretability we have today (compared to capability) it would have been devastatingly disappointing."
I think this is a situation where both things are true. Much more progress has been made in capabilities research than interpretability and the interpretability tools we have now (at least, in regards to specific models) would have been seen as impossible or at least infeasible a few years back.
My understanding is that a few years ago, if we knew the degree of interpretability we have today (compared to capability) it would have been devastatingly disappointing.
We are climbing out of the trough of disillusionment maybe, but to say that we have reached mind-blowing heights with interpretability seems a bit of an hyperbole, unless I've missed some enormous breakthrough.