Some games, yes. Some games, no.
It could also be fighting games just aren't as big as they use to be in terms of market sales. Would Tekken sell that many copies if it was PS3 only? Same for Dead or Alive..
But yeah a lot of titles won't worth going multi. I don't think I would cry if I couldn't get some of those titles on the 360 but that's just me.
You also have to factor in install base. PS3 levels vs PS2 levels.
It's just that simple.