Labour have decided that to achieve electoral credibility they have to run a very tight ship and not just borrow (even more) to cover stuff we can't really afford.
This is, of course, a political choice. But going the other way, the most recent example is Truss, borrowing for tax cuts. I hardly see that as a wise policy, but your mileage may vary as they say. I do get the feeling that a lot of people want tax cuts but no cuts in spending. Is that credible? It seems to be if a Tory does it, but not anyone else. For my part, I don't see how it can be sustained. You end up with even more austerity, maybe the complete destruction of public services. (Which many Tories would like!)
Labour has gone the way it has precisely because of what happened to Corbyn, and his menu of policies that people seemed to think not to be credible.
Various factors have fucked our economy, and it's infantile to think we can put things right without either cutting costs or increasing taxes or both. In the case of cutting costs, everyone is fine with that until it hits them. In the case of increasing taxes, everyone is fine with that until it hits them. The consensus is always - someone else should pay, not me.