It massively disadvantages the company. Why pay for software to be built that can just be taken by your software engineers, who form a new company and run a competing product?
Well if that were the situation for all companies, the answer to why pay is the same as it is now - even if it doesn't provide so much of a moat, they have a business need for certain code so they pay in order to have and run that code.
(I'm not sure if it would be better or worse myself, I suspect it might not make much of a difference when everything balances out.)
Why not? Why as a developer wouldn't I go to a VC and say "I have the source and rights to this premade product - fancy giving me some cash to take my team and run it?"
