i mean, i know the ESA's been trying to cater to everyone and failing, but what was the worst that's happened so far? Sorny not attending? well they didn't attend last year either. i know geoff keighly said he wasn't going to show up either, so that was kind of big and also a bummer. but 95% of e3 hadn't changed and 95% of publishers/developers were still showing up.
i know a lot of the big names stomp their feet loudly, complaining about how e3 is done, but this isn't really a new thing. remember back in the day when they had a much smaller and more 'professional' e3 and that abomination that was e4all? they were both such embarassing travesties that everyone came running back the following year.
edit: mostly agree with nintex