I never saw that movie.

The aftermath of the hippy movement, I think, was positive. I think every has realized where they went wrong, but I also think many people have come to appreciate where they might have been onto something.

... I'm not sure I want to get into this one.

Also also also, Pet Sounds wouldn't have been possible without the LSD influence. Along with some other great music from that period.
Drugs can mess a person up, I couldn't agree more with that, but that doesn't negate the fact that in certain contexts they can contribute to making some great art. Of course, the problem then comes when people start thinking that you 'need' the drugs, that they're like a magical creative tool, then you start getting crap like the very samey acid-rock stuff from the end of the sixties.

I think that's true, especially when it comes to sense perception. The same would be true for things like mushrooms and peyote as well. And obviously a strong sensory awareness is an important part of creating art, especially music. Then you have things like ecstasy which can alter people's emotional processes, which again can help generate a new kind of artistic product. We couldn't have had the great explosion of dance and electronic-based music we experienced in the 90s without the culture of e in the background, I think.
However, I hate the when people treat drugs like a cult or religion, where indulgence is compulsory and everyone who refuses is treated as a square that doesn't 'get it'. This misses the fact that there are people out like there like Frank Zappa, who can steadfastly avoid drugs but still make really angular, avant-garde music just through the way their minds are atuned. I don't think abstract classical composers like Stravinsky or John Cage were particularly know for pill-popping. Artistic scenes that are centred around drug use, like San Fran in the sixties, can actually be very conformist in ways they're probably not aware of.