The article mentions at least one reason why the incentives often aren't aligned: a carve-out agreement that guarantees specific people (often founders) a cut from the "preferred" part of the pie. As I understood it, this cut is completely unrelated to the amount of shares (common or otherwise) those people own and is a separate agreement saying that they get eg. 10% of the money in the event of a sale.

Often, founders get paid money directly as part of the acquisition to make them greenlight it.

How often is often? Can you name 3 such cases?

Often enough that it is mentioned in the article.

Carve-outs in general are mentioned in the article. A common type of carve-out: the employee retention pool. The article does not say that founder carve-outs are common. I'm sure they've happened, but you said they happen "often", as a way to get founders to greenlight deals. Do you know how often that happens?

I don't know how often that happens, so I can't add anything to that part of the discussion.

I can only reason that it depends on whether the founder still has voting control of the company, but that's implied with "greenlighting".

WeWork is a similar situation where the founder is effectively getting a carve-out to greenlight the deal. That's only one example, though.