I'm flattered to know that you think we're the only competitors in the space. However, given that you have several times as many full-time developers as we have part-time developers and my code was/is the basis for critical features in your product, I think you're really overstating the caliber of your developers. As for your "critical mass of users" that we supposedly lack, I suggest you consult Google Insights.
While I don't know the specific details of your agreement with Elsevier that make you so "well positioned to dominate," I do know that your target market's principles are more closely aligned with ours than with yours, and that they aren't stupid. You can't really preach open access for years and then sell yourself to the OA movement's greatest enemy and expect that no one will notice.
In any case, I welcome the competition, although I hope that in the future it comes in the form of shipped code and not more lies about the viability of free software.
FYI - I'm a member of the Zotero core team, but I'm also a graduate student in neuroscience at MIT.