While I would really like a few more Hendrix good albums to listen to, I don't think he could make it through the 1980s drug free. The music industry is going to move in its Disco and then pop direction no matter what. The popularity of his music is going to fade a bit just like all the other 60s rock act during that time. Thats going to put huge amounts of stress on him.
Sadly I think it was for the best that he died young at the top of his game. I'd hate to think of Hendrix dying on a toilet a fat has been like Elvis, or freak like Michael Jackson.
Oh, I think you forgot about the First Rennaisance of Guitar Rock in the form of the few good acts of Hair Metal, not to mention the rise of Experimental Instrumental Rock of the likes of Steve Vai and Joe Satriani. Imagine if you will a late '80s benefit concert with the finale being a five-way guitar battle between Hendrix, Vai, Satriani, Slash, and Eddie Van Halen!
I also think that his career could get a shot in the arm (so to speak) if he was in either
Blues Brothers movie, the way it did Aretha Franklin, James Brown, Ray Charles, and B. B. King. And the likes of Dream Syndicate, Lenny Kravitz and Jack White might actually intern under him (or try to). Then again, he might denounce them as "plagiarists" and "frauds" the way Joanni Mitchell has done to the likes of Natalie Merchant, Alannis Morrisette, Averil Lavigne, Michelle Branch, Dido, and even Gwen Stefani!
The real question is, would he stay with Fender even through the "bad years" of the mid-70s to early-80s, or would he move to the multi-humbucker Dark Side of Kramer, ESP, Schrechter, or Ibanez?