I have an (almost) fully specced M2 Pro Mac Mini. Totally sufficient for all my music production needs (which does benefit from many cores). No reason to get a Mac Pro.
I think a lot of the 'mac pro' thinking from 15 years ago was you needed a 'big pro machine' to do serious work. Nowadays, these machines only eat up space, energy, produce noise and while they can be faster the returns are diminishing and you don't need it for a lot of serious tasks. It's a bit of the Unix workstation vs PC market repeat. While some people will hold on to their 'big PC' as long as they can Apple (and hopefully others) will release vertically integrated small machines that offer serious performance and eventually will take over the market.
I just replaced my 9-year old Macbook Pro with an M2 mini and, understandably, it feels like a massive upgrade. But the laptop didn't even feel particularly old after a decade, just 'underpowered'. I've realised that upgrading is a nice option to have, but it's even nicer just to not need it in the first place.