I don't see why squad didn't sell KSP before it came out of beta. They are probably not going to give it the attention it needs, leading to bad publicity. Meanwhile, I'd venture game companies'd be willing to pay a pretty nice sum for it.

Good they didn't, I'm pretty sure anyone willing to buy a franchise would just milk out every penny they could out of it and let it rot. KSP progressed pretty nicely out of beta and through several updates.

That said, it's pretty sad to see development stops. At least they AFAIR sorted out the modding API issues, ensuring a stable platform for the community to work on. Honestly, that's what makes me believe KSP will be still improving in the coming years - the modding community is strong and have already pulled off incredible feats of programming and science (this game attracts a really specific crowd).