First, if they are, then that's part of the focus of the article. That guitar and guitar rock is waning -- and surely Diplo and TSwift are not bringing it back.
Second, no Diplo and TSwift are not as legit as SRV and Dylan. Not because they are different genres, but because they are inferior artistically (regardless of genre).
They might be equally entertaining or whatever, in a "it's a free country and I can listen to whatever I like", but artistically they're not even close (and SRV is not in the same league for cultural impact as Dylan anyway).
It's not about the past. There are contemporary electronic, edm, r&b, hip hop etc artists that are on par with SRV and Dylan on creative merits, but TSwift and Diplo are not them -- like the Monkeys weren't as good as The Beatles, and Frankie Avalon was no Elvis.