Interesting question! My guess would be yes, there would still be hippies. Vietnam wasn't the only thing that contributed to the hippie movement, although it was a big one for sure. Music, fashion, attitudes about sex ... those things also made the hippie movement. The focus would have been different. You aren't going to get half a million people to march through downtown San Francisco for hair styles. But I think there still would have been a hippie generation.
A big factor was the post war baby boom. For the first time there was a whole generation of young ppl coming of age at the same time that outnumbered the older gen. (That population surge is still going on as we now break the Social Security system for you younguns') I was in the military and police force during the early years of the drop-out gen but by 1970 fell into the free love youth culture that was taking over. The Vietnam war was the least of my concerns, tho young men were still being drafted or going underground to evade the draft. We were divesting ourselves of the post war materialism that our parents embraced as well as dumping all that contrived propriety under which we were raised in the '50s. "Why don't we do it in the road?" was not just song lyrics, it was a philosophy. We could also have relations with ppl of the same gender or different race, both taboo at the time of our parents.
I was born in 1973, so all I've got is second-hand information about it...but it seems to me like the hippies were more a result of post-WWII existentialist thought and the freedoms granted by access to birth control. The peace movement certainly gave them something to rally around...But this was a time of great change. There were many social movements. If it hadn't been peace, it would have been something else. That's my guess.
I think these are absolutely correct. I also think it should be remembered that social attitudes go in cycles. There had been "hippie generations" before the 1960s, and presumably there will be again. The next one will be different, obviously. Who knows what it will be like, or what will trigger it?