Cost was higher before and we had more tanks back then. Outside of most flashpoints without tanks there is no endgame content.
BioWare releases good, challenging, regular progressive content and repair cost will have nothing to do with the number of tanks. Tanks will be there because without all three; tanks, healers and dps, there is no way to do progressive content.
The guilds will have their tanks, that's out of question.
I was talking about random group finder. There weren't a lot of tank before and I don't think more people are going to list randomly.