Djokovic and Murray emerged, when Fed was racking up majors against a bunch of nobodies and teenagers. I think today’s younger generation is just unlucky, in that they have to contend with several of the best players ever, maybe the 3 best players ever, all at once.
It won’t last much longer, though. Fed is clearly fading fast, and Rafa and Nole won’t be far behind. A few more years at worst.