That's literally there in the definition of a VC-backed business model. You get a lot of money now, in exchange for some amount of ownership and expectation that the business will grow, whether it makes sense for it or not. The investors want a return on their investment, so they absolutely will push the business past the point of breaking; if they can extract their return before it burns down, then they win.
Or, in short, from investor PoV, startups are cattle, not pets.
I'm sure they still still grow, because SE is an incredibly useful product. But I think a bad leader poses a serious risk of constraining natural growth by pushing monetization too hard and driving away organic growth.
The best way forward is for someone with a good reputation to take the content and launch a new server, as Spolsky himself always said should happen when SO one day jumps the shark.
So they find a buyer for the business, transition things, cash out and go find something else to do.
The investors set a goal and Joel executed it.