Music is in your soul....just because you can play technically, doesn't mean you have the soul to feel the music, just like people that can play, and feel the music, might not be able to read sheet music.
There are no rights and wrongs....just what's in your soul. If people played music by the rules, there would've been no Jimi Hendrix, Pink Floyd...or untold numbers of old blues men, that helped shaped the way rock and roll came to be. No go get Rosetta Stone, for English, so Ace can type on his keyboard, without punching his monitor.
I really don't believe that Eddie Van Halen invented drifting....he may have used it enough to bring it into main stream guitar playing...but I think the only thing he invented was over priced signature model guitars, and obnoxious arrogance, when discussing his over rated talent.
But I can't be sure....
About the drifting part....