Someone founds a company because they want to be a leader, not a follower. Entrepreneurs have a difficult time when the acquiring company tries telling them how to run the business they have created and grown.
When the acquiring company is successful at getting the founder to stick around, it’s typically because they’ve learned to give their founders the latitude to run their startup as an independent unit within the business. You’ll hear these founders say, “I work for Marc [Benioff]” or “I work for Jeff [Bezos]” rather than “I work for Salesforce” or “I work for Amazon.”
In this case the startup founders get direct access to the CEOs. Nothing changes for the startup except who owns the company.