I admit that if long solo sticks it can be anticlimatic. Should it fail to be great racing or should they prohibit solos?
Is this fault of rider attempting solo or peloton for not reacting?
It's not about who is at fault. It is nobody's fault.
It's about tension and uncertainty. Who is going to win? Are they making the correct decisions. When Pogacar is racing, there is almost never going to be any of that. You know he is gonna win, there is no uncertainty when he goes solo, and often the riders behind instantly give up and start riding for 2nd place.
The only races where Pogacar adds something is Sanremo, the cobbles, and The Tour, and the latter only if he's at a similar level to Vingegaard. Take him out of the last Tour and it doesn't change all that much although probably Evenepoel poses some problems in the hills and on the gravel stage.
In the previous era, long solo's were spectacular because they weren't the norm. They weren't expectable, and when they did happen, they often went wrong too. Contador built a reputation for crazy attacks in the 2nd half of his career, but they went wrong a lot more often than they went right. Same for Nibali and the rest of that generation.
And these guys would find themselves into situations where they were behind and had to do something. Pogacar has been in such a situation like once? And he tried, sorta and went back asking if he could just try for the stage win instead.