Sure but I feel like they fit the vibe of the festival more than Kanye does. Maybe I’m wrong though

That is nothing new. People have been covering each other since the beginning of music just the technology and aesthetic has changed.

As for the sampling you are referencing, that has been happening in hip hop for a very long time. Many people have used the same beats and samples to make songs that are almost identical or entirely different.

a boy is a gun - tyler, the creator

and

Bound 2 - Kanye West

use the same sample but are completely different songs.

Bound - Ponderosa Twins Plus One

Eh, I don't really care about any of that. If the artist is performing something true to themselves and is inspired then it is okay in my books. Knowing music theory is great but sometimes it can get in the way.

I mean Kanye headlining that year was a sign of things to come.

Rock is kinda dead. There are tons of small groups doing great stuff but there are few quality rock headliners these days.