In a VC's eyes, a "zombie" isn't just a time-sink; it's a prison holding back good founders and employees from doing other things.
If the VCs are not the sole owners of the company, that will get them a lawsuit from the other investors for breach of duty as a director. Often the VCs don't have the authority to kill the company.
We were doing fine, but not awesome, and then management started taking big risks and we flamed out. Very frustrating to spend time and effort on something you know is killing the company.
Practice intellectual self defense: Read books, and lots of them, read the comment sections but skip the articles, and engage in communities online and on the ground to gather your own information about the world.
I mean, yes, obviously, it's rude and unpleasant to say "I don't have time for you because you're not making enough money," but it's a lot more unpleasant to say "I'm firing you and all your employees even though you're making a profit because you keep asking for favors and it's annoying."
2) If you cut ties with entrepreneur A cuz you think his company is zombie, he doesn't tell you about entrepreneur B who is about to start the next big thing
3) i.e. it's like high school. You want to always be in the right crowd invited to the right parties. And if you stop associating with a certain group of people, you better be sure those are not the future kings.