I somehow got a hunch that the recent overfunding trend made startups as inefficient as large companies are, so there's not much incentive left for acquisitions if you can simply copy it in-house for much less.
If a company prematurely captures their upside by raising an excessive amount of capital they create a scenario for new employees where they participate in the upside only after the desired (10x) multiple is realised on the prior raise.
Except if a company is inefficient, the founders may find a way to get what they want without waiting for that 10x to realize. I'm not sure though why the investors are seemingly OK with that.