It really looks that way, cause Pogacar is 3 years younger. But I have a feeling it will be opposite, that Van Der Poel will end up as a more succesful classics rider.
I think Van Der Poel will last longer, and after this year I think he will fully focus on the road career, aka the classics, cause these are the races that will lead him directly into pantheon of greats of this sport.
Pogacar on the other hand, I think will burn quicker than Mathieu. He emerged as a youngster, he targets everything, his style is relentlessly atacking... If he doesn't change his approach, I'm afraid he won't last that long, and plus I have a feeling due to his relative Grand Tour failure last two years, that he will more and more want to turn focus to these races.