Capitalist funded the creation of the iPhone and withdrawal rent on their funding.

There are many ways to fund the process.

Capitalists like capitalism because they get to extract more than they funded with no upper bound.

They leech off of the value of the workers who created the product because they think funding the arrangment entitles them to infinite returns on their investment.

It's rent seeking with more steps and no overhead. There is zero upkeep because the input is the output, capital.

If capital was additive then adding twice as much capital would result in twice as much output and that is clearly not the case.

It's a valve and it is like a damn operator taking credit for the river.