I think we are partially to blame for this too though. For the last 10-20 years the whole goal of a founder was to grow a business, get acquired then exit. If founders instead focused on building a sustainable business maybe we would have a more diverse tech landscape.
To be fair, even the ones that don't want to get acquired know the bitter road ahead from the opposition aggression.
Nobody would fund a founder who wanted to build a sustainable business. It would have to be bootstrapped, and there are a lot of such businesses, but you never hear about them because they stay small.