How much does a graduate student need to live on?

“Is CEOs COOs VPs of marketing considered to be better than CSOs or VPs of R&D?”

“Considered to be better” by whom? They are different jobs - it depends on what the person wants to do. It’s like asking - is being a doctor better than being an architect? Well, yeah, if you want to be a doctor, and no, if you want to be an architect.