A VC fund makes its money two ways: a management fee — typically 2% a year — and carry, usually 20% of the profits. Both of those checks are written by limited partners: the pension funds, endowments, and family offices who fund the fund.
The founder pays the VC nothing. The founder pays in something else: equity, board control, and the right to be replaced. The LP is the customer. The founder is the inventory — sourced, packaged into a portfolio, and sold, at a markup, to the people the firm actually works for: The LPs.