Things tend to exist because they're popular (QWERTY) or good (DVORAK). While there is certainly "evidence" in some form for meditation, it seems to exist mostly because it's popular.
If meditation is actually good, and it eventually permeates society, I'll just be a late adopter. No account I've ever read has pitched it as so wonderful a tool that being a late adopter would be terribly painful for me.
But for now, I'm predicting that meditation will be a fad. I don't expect to see ~5-10 meditation centers in my hometown in 15 years.