Re: Is this the boat shops fault?
Putting the cost aside for a moment I would agree that electrical is better vs mechanical. I was basically forced to switch to an electric pump when I upgraded my 4.3 to a 4bbl carb because the carb didn't have an overflow fitting for the diaphragm sight tube. In the process of replacing the pump and blocking off the boss on the block I noticed that the pump was very slowly allowing raw gas to leak into the block, thinning the oil dramatically which could have led to eventual bearing failure. The diaphragm was intact enough that the sight tube was dry so the problem was invisible. Also with the electric pump you have the option of adding an oil pressure safety shutoff switch should you lose oil pressure while motoring. Both of these benefits are unique to the electric pump. And I would argue they are more reliable than a mechanical pump if only because that little rubber diaphragm will stretch and contract millions if not billions of times during its service life and become increasingly dry and brittle over the years.
That said, it sounds like they're charging you retail plus a markup plus labor for all OEM parts. If you told them to just install the motor, transfer the accessories over and leave the fuel system alone you could definitely do the job for less yourself but that's a question of how much plumbing and wiring you feel like doing.
