It's really hard with boxing as it's not an objective thing to judge like athletics, where you can actually take 2 athletes from different eras and compare them. There's no hard evidence to reveal if someone is actually as good as SRR, so it's all subjective.
We already have one even greater and we are lucky to be alive during his era. I'm sure you know I'm referring to the great Raymi What light flyweights do you know of that could KO HWs in sparring
Even if we are to have fighters of his quality, it's really unlikely they'll reach the frequency (and opposition level) of Robinson and fighters of the past. There's little reason to fight so often. How many greats of the last 2-3 decades have that insane amount of fights? J.C. Chavez. Not as many, but James Toney.
Floyd is the closest thing to a SRR in this era. He is pretty close, not there but he isn't that far off.
Dura is the closest 70-1 Beats srl out of his own prime Gives prime Hagler his best fight even though Duran is much smaller Beats Barkley No one else Roy jones was the only other guy in history who could have been but.... You know Title defenses against can drivers really really looks and no matter how you cut it
Sheer number of professional fights and that good? Not in my life time. As good of a fighter? Of course there will be.