That is not actually what happens with most acquisitions, especially not in the drug and biotech space. Big enterprises buy promising startups at the phase 1 or 2 stage fully intending to bring them to market. But still many fail to ever make it through phase 3 and gain FDA approval. That's not an innovation problem it's just the nature of the business.
I am not sure if this applies here, but Regulatory Capture is a certain way to block the small players from growing. I understand that drugs are a special case, so I do not know if that applies there.
Also, the fact that a product fails post-acquisition is precisely what happens a lot in regular business too. They can be seen as a threat to other fiefdoms in the behemoth, or they lose their autonomy. Doesn't always mean the product or idea was flawed beyond repair.
