I'm going with yes and yes. As has been pointed out, modern fighters simply don't fight enough to make a serious run for a top spot. For the debate to change, you would have to have some significant finding for Langford or Greb, e.g. film that portrays them in a very flattering light. Or maybe someone will come along and present an angle that gives a fresh perspective on matters.
SRR as great as he was I do not rate #1 p4p all time, I think that honor should go to Harry Greb, I also think thereÅ› a good case for Willie Pep, Roberto Duran and Henry Armstrong being rated ahead of SRR.
The sport will have to change radically again for anyone to come close to his amazing numbers. But if you emphasise dominance, I can see someone doing another Roy Jones but better and having a case on just being so ahead of the pack. Let's say that Jones faced and easily beat McClellan, Eubank, Benn, Nunn, Collins, DM and dominated Hopkins and Tarver in the rematches before retiring in late 2004. Well, then I'd think he'd have a good case, and while I don't think anyone will do anything like that any time soon I wouldn't completely rule out it happening.
Actually, he always says that anyone pre-1960 sucks, but in this case he has to defend his favorite SRR who also fought in that "shitty" era.