Ultimately, even if your worst case scenario were to play out, it shouldn't matter. The Bitshares network will be alive, well and competitive. Once the network grows it will become truly autonomous which is where we need to be anyway. It is the Bitshares constitution/protocol/usability that hold the true value, not who is working for it.

Assuming CMX stay "committed" to bts for another year or so it shouldn't matter if they decide not to work for bts members anymore.
Worker proposals can hire new devs if need be, but I think a feature-freeze is a good idea. So I doubt we'll want to hire any new core-devs for a while.
Even if things go sour, members can vote to burn all dilution for a while.
DPOS 2.0 should launch with nearly all the killer features we need.
Let the referral system do all the work for a few years.
I trust them at least not to dump in such a way that tanks the price, but how they manage their private money is up to them.
I'm not even sure what "big company" could steal CMX away entirely from bts.
No centralized institution is going to be able to fill the boots of BitShares - why would CMX sell their shares and miss out on the bts revolution.
TL;DR There is a market niche for a global unbounded organization that efficiently adapts and morphs to the needs of the market and the desires of it's shareholders.
I believe BitShares is that organization.
Nobody/nothing else that I've seen can offer CMX the opportunity to benefit from filling this market niche. Why would they even dump their baby when it's got so much more growing up to do?