I think a lot stems from the way Remco rides. He doesn't really have a fanastic jump, so all the races he wins it looks like the competition wasn't watching/interested or not in form.
Take roglic in this vuelta for example. The general consensus is roglic is far from his peak... yet yesterday he did a 27minutes @ 6.2-3W/kg. This is just at his best level. (lowered it by .1 because of drag compared to Remco). We just assume he can do a lot better because people aren't used to him being dead at the end. But thing is Remco is pushing extremely good numbers this Vuelta and with those numbers you don't ride away from him. Last 3km he did 6.8W/kg... It just doesn't look flashy, he isn't sprinting, out of the sadel,... So I think most people misjudge the speed at which he does things and that it looks like the others dropped the ball... instead of other people being peak isn't good enough.
I think this is a fair point, but some of it is also the assessment of competition. Vingegaard similarly just rode Pogacar off his wheel without a big acceleration, but that was awe-inspiring because he was doing it to Pogacar. Remco has not managed to drop Enric Mas, who has not been a true contender to date though perhaps that has changed.
Similarly, Roglic appears to be off his best because he is usually well ahead of Mas, not behind. And he’s numerically still a bit off his best from what I understand, though not far off. Then there is the logical assessment of context: Having dropped out of the Tour with two fractured vertebrae and being completely off the bike for a month with only 10 days of riding to prep, how could he possibly be at his best?
But numbers are also numbers, and it appears Remco is very, very strong.