Do you ever wish to work on something that hits more personally for you? Would that motivate you more than just the pay?
edit
by owner, I don't mean of the company; rather the product. I find developers spend most of their time in the app and know when something works or doesn't. They can have a "hunch" when a feature is off, or the experience is wrong. being empowered to make decisions and tweaks without someone else getting upset is invaluable
I'm an independent contributor, a dev. I don't own my employer's business beyond some token stocks. They give me value in the form of money because I give them more value through my work.
It's ultimately prostitution, and that's OK. They pay me well and respect my time/skills, I give them 100% for 8h day. But I won't go "above and beyond" for someone else's business...