My gut feeling is that a far lower percentage of the peloton is doped than 10-15 years ago...
probably partially because of the back-lash meaning more guys than before would just say no, especially if they already
have contracts for multiple years and perform at an okay level.
But what if their performance remains the same but good becomes mediocre, wins become hard to achieve top 10s, what if you have to push the watts you needed to get into a break, just to stay in the peloton?
But whatever has happened in the last ~3-4 years? I find it pretty inconceivable that a decent %, including most of the top GC guys, are pushing the limits of what is legal, and stepping over those limits.
Dumoulin, Pinot and Bardet are the same age as Landa. Their performances over the last ~5 years (pre-retirement for Dumoulin and Pinot) from what should have been their "peak" at say age ~24-27? Yeh, they either got worse or stagnated. As human physiology says they should have.
Yet Landa (their peer who at age ~24-30 was a very similar level rider overall to those 3) is now putting up numbers that would have made him DOMINANT from 2014-2020... a time when he generally was fighting for podiums.
It's really not just Landa, apparently Thomas (!) was pushing his best watts ever last season. Ever, that's better than when he won the Tour and he got beaten by a beat up Roglic for the Giro. Bernal also pushing his best watts ever this season (guess not at the tour, but the fast they are going, who knows? And it's really not just them, the overall level of many many riders has just made a jump. The overall speed has gone up, all the climbing times are much better than before, even absurdly better as we've seen on the weekend on two occasions. Not only did even Remco beat Pantani's time (and it wasn't close) a lot of riders did times competetive in the 90ies.
So while Pogacar's and Vingegaard's dominance are extreme, they are the tip of the iceberg. A very sharp tip, but only the tip. There's also the possibility that they are just really extremly talented and this is massively amplified by whatever is going on.