First couple of times I went to the States (late '90's) there were free alcoholic drinks but since then I've only encountered it once, not sure who I was flying with. And that time in front of me were 3 men, all middle aged, who were completely obnoxious and got more so as the flight went on because they kept asking for, and getting, more free alcohol.
I'll have 1 with my meal and maybe another if they come by again, that's it....I think some people abuse it and for this reason I think I'd rather they charge for it.