I think their equivalents now would be:So what if there were someone born in c1985 with exactly the skillset of Merckx, or Kelly, Hinault, Anquetil, De Vlaeminck or Bartali: what palmares might they have now, as they enter the final years of their careers?
Merckx - Nibali or Valverde. Froome if he wanted to be
Kelly - Alaphilippe
Hinault - Dumoulin
Anquetil - Dennis
De Vlaeminck - Gilbert
Bartali - the sport was so different back then I see Thomas De Gendt, riding alone or in small groups most of the time
These all time lists will always struggle because of the changing eras. More so than most sports. The likes of Binda and Girardengo have more in common with RAAM rider than Nibali. And importance of races changes. The Vuelta has never been more prestigious, while Paris-Tours was once the equal of the monuments.
And then there's the breadth of competition. In Merckx's last Tour win 125 of the 130 riders came from just five countries. The last two season's GT winners have come from Kenya, Wales, England, Ecuador, Colombia and Slovenia.
A better way of looking at it is a fairly strict Road Cycling Hall of Fame. Five current riders will have booked their place unquestionably - Froome, Nibali, Gilbert, Sagan and Cavendish. Valverde would be a sixth but may fail entry requirements. Recently retired inductees would be Contador, Boonen and Cancellara. It's strict enough to exclude Schleck and Sastre and probably Wiggins and Evans (the latter two have crossover genre appeal). Poulidor's out, Zoetemelk too.