This is a difficult situation to deal with. From a business PoV, I can completely understand the apprehension from ESL. Immediately putting money into an unfamiliar scene (edit: it's been a looong time since they were here) with no guarantee is a pretty decent risk. If the comp scene boasted 10-20k more players than it currently does, I think there wouldn't be an issue with them probing the scene with a few experimental cups to see the turnout and success. However, This isn't TF2's first rodeo with prizeless tournaments, or ESL. The TF2 community is one that has been frankly abused by its developers, coupled with organizations/leagues that seem to only feign interest in the game long enough to say "nope not for us". However, in my opinion, ESL (nor any other league) can simply ask a grass roots, community run, competitive scene to ditch/switch from a reliable community infrastructure to one that could be gone after its second or third tournament/season. Also, locking down to just EU immediately kills the interest of (guestimating) 40-50% of TF2's competitive community.
So I guess what my personal response to ESL would be pretty much summed up by corsa. Don't expect effort to be put into your cup if you don't put effort into the community.