Where are you playing? I think I've seen maybe one (could've been the clone) being used in my decade airsofting. Seen an awful lot more ICS L85s, G&G F2000s, TM/CA AUGs and other bullpups than I have TM FAMAS's (famii?).
I'd say the Tar-21, L85, Aug and F2000 are all more popular
Either way it sadly seems to be because the production runs aren't huge and the factories quite often retool to produce the next model. There's a fair amount of interest in a new G3 supposedly but I guess we will just have to wait for WE to remember that they are meant to be producing one.