That's because many corporate "donations" are not so much a donation as a way of soft-buying a feature.

It's hard for businesses hyperfocused on short-term gains to understand a long-term value of, for example, supporting an alternative for an industry-dominating Adobe toolkit. But the value is there.

Long-term value that's hard to define doesn't translate well to stock price especially when any investment also helps competitors who aren't investing anything into the project.

Krita is accepting corporate donations.

And the examples are? Cause the counter examples are phenomenal like Blender and Linux.

Khara threw a bag of pachinko money in Blender's face to make the last Evangelion film work, and it was fine. I guess that was a rare occurrence that they desperately and so purely needed a tool they can hand to broke freelancers without frantically searching for keygens, but it can totally happen when incentives are right.