Studio wizadry is too strong and getting into a studio or a makeshift one is easier than ever. In the past, regardless of genre, you had to have live performance skills which you then transferred to the studio.For you to even have the guts to approach a studio, people had to tell you you were good first. Nowadays, that training process isn't available for modern singers/rappers/deejays, and they lack not only stage presence, but overall showmanship.
I'm often perplexed when I see a singer who can't sing live, and I wonder, "Who around you gave you the confidence to ever step into a studio?" And the real answer is that they had no guiding hand. And once they have manufactured a hit song, they can just rely on that, but if you look at the live performance, there's nothing. Imagine a "Rumble in the Jungle" in this century, which performers can come and work a crowd à la James Brown, Celia Cruz etc.

Very few. These youths can't even release live albums.