You are completely right in this case. Sometimes, when the company is not doing well and the founder CEO is not hitting the performance targets agreed on earlier, the VCs will fire the founder and install one of their MBA buddies to try to turn the company around. This is usually a condition of further funding when the company is in a weak negotiating position and on the verge of shutting down, and it's incredibly unpleasant for everyone involved. However, the executive implants only come in when the company is circling the drain. It's basically failed at that point, and the founders get nothing. Sure, the executives may get a big chunk of equity to lure them into a company that's going to zero, but barring an incredibly rare miraculous turnaround, that equity is completely worthless by the time the VCs get their liquidation preferences.
All of the things you describe are aspects of bad startups. Things are very, very different in good startups that are doing well, even the VC funded ones.