Yeah, there is always the UGC 6s League people can transfer into which is free too, idk how well run it is though.
as far as i know most of the higher level players get along very poorly with the UGC admins and consider the league somewhat of a joke. the skill level is much lower anyway, comparable to the average pub or ETF2L div 6
NA competitive tf2 relies almost entirely on ESEA for its big "spectator" events* (the LAN tournaments, etc) and would probably collapse very quickly and messily if ESEA were for whatever reason not in the picture. they'll probably just rationalise it away. as much as possible.
i don't think CS has anywhere to go either.
w/e rapidly losing interest in these games anyway
* read: "almost 3000 viewers!!!"