I don't need to remind anyone here that we cannot really compare riders from different eras. We can't truly know who is the fastest of all time because we cannot compare riders in their primes on the same equipment.
But what if we could?
Let's say you have a time machine and can transport any rider from one era to another, and race them at one track on the same day with equivalent equipment from the day. What happens then?
Assuming you give each rider some time but not a lot (a few weeks at most,) to acclimate to his new bike/track/era, here is what I think would happen:
Riders from the '90s would suffer comparably outdoors. The guys from the "Golden Age" just before trained harder (Ward, O'Mara, Bailey, Hannah,) and the guys from the RC era did as well. Even the riders from the '60s and '70s were tougher, as their machines required more strength and endurance to ride. In long-moto formats, the conditioning factor would come into play. For instance, Bob Hannah or Roger DeCoster would beat Jeremy McGrath or Jeff Emig outdoors on equivalent machinery, IMO.
Riders from the pre-evolution days would suffer just from not having the speed. Sure, they were fast, but the meaning of the word fast has changed. This would also be true of any '80s rider moving forward into the late '90s or early '00s, to a lesser extent. The fact that an '80s bike could handle so much more abuse than the ones before, and the fact that the speed of competition has risen since then would be detrimental to the riders from earlier eras. They would have to adjust. Even a lesser talent from today would probably beat a notable rider from the past on today's machinery, just from speed alone. Dean Wilson beats Brad Lackey, for instance. In other words, the speed of the race itself has gotten faster over the years.
"Hungry" riders would do well in any era. RC, DeCoster, Hannah, would rise to the top in any competition.
Current-day riders would have a hard time making pre-'80s bikes go fast. Jeffrey Herlings would get smoked by Heikki MIkkola on '70s bikes, for instance. Even if he could go faster, he would destroy his machine before the finish.
Let's hear some takes you have and discuss....
Braaapin' aint easy.