What you are describing is exactly the principal-agent problem, and it is a real problem at startups when a founder is truly motivated by something that the investors don't care about. You can run a company with different motivations than your investors, but only so long as you return the goods they want. If they see you not returning the goods and not caring about that fact, they will try to replace you. They will try to do that a lot faster if you demonstrate that you don't care about giving them a return than if you show that you do care.

Conversely, investors can be mission-driven or otherwise aligned with you on something other than "maximize my return," but those investors rarely give you the best price.