EOS forks need approval of at least 15% of the original token holders, so I really don't expect a plethora of different EOS chains, but rather 1-3 major ecosystems, where a DEX should be an important element.
I mean, yeah it's nice to have an EOSFinex around, but a Bitshares-style BTS working as a DAO is much better I think.
Keeping in mind the fact that those 15% (and the remaining 85% for that matter) will participate in all those chains, I'm thinking the figure may be more realistically put between 10-30. 😋