Harry Belafonte is hard to classify. You could consider him world music/Latin-related, or you could simply classify him as pop (he is not in either early rock and roll and rnb world).
Since he was not nominated in the first several years of the ballot, he probably should/would always have been, early influence candidate regardless. That's why I didn't include him on the list.
Rolling Stone will probably update their Greatest Albums and Greatest Singles lists again sometime around early 2030. When they do, I think it'll be really interesting to see which artists have gained more recognition among younger generations of music fans.
We might end up seeing some artists who were largely overlooked by us today, but who have actually been gaining more respect and influence among younger listeners over the years.
Kate Bush is probably the best example. Back in the early 2000s, I don't think many people would have considered her a serious Rock Hall candidate. But over time, she gained a huge amount of popularity and critical acclaim among younger generations. She finally received her first Rock Hall nomination in 2018, and was eventually included in Rolling Stone's Greatest Artists/Albums lists around the 2020 update. Then Stranger Things happened, and suddenly her induction basically became a slam dunk.
There will always be new Kate Bush out there, artists who might not seem quite obvious right now, but whose value gets reassessed as younger generations discover and embrace their music.
I also think we have to consider what happens another ten years down the road. By then, someone like Taylor Swift could be one of the established old guards of the music industry, with a lot more influence and institutional power. Maybe a phone call from her could help put someone like The National or Bon Iver on the Rock Hall ballot. Or maybe Olivia Rodrigo openly talking about how much she admires Tori Amos could help push the Hall toward giving Tori a nomination.