So given that do you think De Vlaeminck would beat Van der Poel having had access to all of the same opportunities?Well no ***. One raced in the 70s when pro athletes still smoked and drank, had to write the book on cyclocross technique himself, and is dead now, the other is racing in an era with nutritionists, power meters, performance coaches... and was able to learn the technique which even today is still largely based on how De Vlaeminck passed it down.
Obviously each has to be compared in light of the era they raced in. Not to mention bikes got a lot lighter and there are discbrakes now which completely change the game in a sport like CX.
Not that it matters what we think since its impossible to ever find out but apples for apples Van der Poel's palmares on the road is significantly more impressive.
Another - and a not so fair - way of putting it is to ask if the 1970s peak De Vlaeminck with today's best equipment could've beat Van der Poel. I am pretty sure NOT but that assumes that DeV would not adapt to current environment (eg jumping barriers etc) which obviously is quite an unfair assumption.
I thiink I'll backtrack and say that it's a meaningless comparison, just like that of Merckx vs the rest and etc etc. Enough to say that De Vlaeminck was amazing in his time! (worth watching old races, they're much faster than I ever imagined).