It's a good question. Tempting to say that it is basically the same in football with the players of yesteryears all having more mythical figures because of no social media etc. But it doesn't really translate well, because it is also about style and character which there is obviously still room for in boxing. In my opinion the biggest issue is promoters and the fighters themselves seemingly being obsessed with protecting careers and legacies. Champions padding their wins against fodder has always been a thing in boxing but the roundabouts to avoid the best fighting each other is taken to an absurd level. I'm not convinced Wilder, Fury, Usyk, Joshua, Zhang and Joe Joyce is that bad of a generation all fighting at the same time but they absolutely do need to Fight each other at the top of the hype. The timelines since Fury returned has been awfully managed. UFC is a good example that you can still generate absolute loads of hype in combat sports when the best consistently fights the best. Jon Jones cleaning out his division, and then creating a persona that made someone like DC obsessed with beating him was fantastic 10 odd years ago. Anderson Silva and GSP always having to fight the best in their division were exciting and made the brand valuable. The heavyweight division were a free-for-all. But it is also an example of where it can maybe go a bit wrong, because even though they are not all the way there yet they have made similiar decisions and adjustments to boxing in the last couple of years. People like McGregor and Jones holding up their divisions at the top of their hype either with escapades in other sports, or picking their fights. People obsessing with their records, or "double-champ" status, either getting protected from styles they don't suit or getting elevated into positions they don't deserve to early making a mockery of whole divisions. Even McGregor were thrown in with a juiced up Mendes in a fight he very easily could have lost very early into his "cash-cow" tenure, and he also had to generate obscene amount of interest and a title-win in impressive fashion before he got the Dos Anjos fight to become two division champ. And even that were farcical, but atleast you could understand it with how massive of a cult of personality he were. But now the standards have fallen, and everyone gets these opportunities it feels like without generating hype at all.
The best needs to consistently fight the best at the right time, and worry about the brand of the competition and not the individual fighter. That is where boxing, and especially the heavyweight division has failed spectaculary for years