It didn’t kill the company for several reasons, but primarily because:
1) The company had enough momentum, revenue, and cash in the bank that they could go on hiring sprees to replace everyone. The new hires had a lot of churn when they realized what was going on, so they just kept hiring until enough replacements stuck around.
2) Many of the employees who didn’t quit saw this as their opportunity to rise through the ranks and fill the voids. They weren’t wrong and it paid off for many of them in the form of rapid promotions and advancement. The CEO became more hands-off as he realized his micromanagement wasn’t helping, so they basically inherited a slightly better situation.
After this experience, I don’t really see a developer exodus killing any big company with good momentum and decent cash reserves. As long as a company has cash flow they can spend their way into hiring replacements as long as it takes.