That assumes that the code itself was what made the company competitive and brought in the money to begin with.
If I were laid off by my current employer, who has a giant sales team and likely thousands of contracts in every state with most of the existing potential clients, the odds of me being able to compete against them somehow dip into negative numbers.
I got laid off from an internet TV company. I could probably replicate their backend systems, and in fact, I did (for one test channel). I definitely couldn't get content licenses to 400+ real channels. Or any paying customers outside my immediate family. Or make a UI.