Apple's money comes from money we have voluntarily given them to own one of their phones and to be part of (and actually we are then forced to be a part of) their market, since only Apple approved software can run).

A government's (a monarchy is a form of government) money comes from taxes from people who wish to be part of that system and benefit from the security and markets it provides (otherwise they can leave. Sort of. But in the past they likely could), and they are limited in what they can do because the government enforces the rules.

It's not totally dissimilar, in my eyes.