Well, my ATVs use vacuum fuel pumps. The pumps are simple and inexpensive. I have an ATV with 2,xxx hours on the engine. My truck has 6,xxx hours on its engine, and has about 300,xxx miles. Theoretically, my truck had 100,xxx miles at 2K hours.
The vacuum fuel pump is easy to access (not in fuel tank).
A vacuum fuel pump would increase flow as RPM's increased.
Everything vacuum-powered would lose vacuum with wear on the rings and cylinder walls.
Oh. Vacuum drives the pump. It does not pull the fuel up. You don't put the electrodes for the fuel pump directly into the fuel, either.