You must consider the evolution of the sport, not only in terms of science and technology, but talent scouting, globalizzation, etc. The pool in the late 60s/early 70s was pretty much limited to continental riders, with the obvious exceptions. Put Merckx in with today's group and, due to his size and structure, he would probably have a hard time keeping up in the mountains or in the TTs with the likes of those at the top today. He was not the dominat climber in his day, but had exceptional performances. Would the benefits, but also the resultant tougher competition, of that evolution allow him to obtain today a superior level of Pogacar? This is an open question. In essence did Merckx have the same capacity (I intentially avoid the word "talent", because science has taken over) as Pogacar now (and we could throw in the various Vingegaards and Evenepoels)? In short, did Merckx have the same power and endurance, minus the sport's evolution, as the Bigs of today? That is the question.