How hard it was to change horse to car, film to digital, fax to email, etc would differ depending on who was looking at the challenge. I expect many of those involved in the existing would have thought they had years of dominance only to discover their dominance rapidly declined. Inboards boats use engines essentially sourced from cars so we can be pretty certain ski boats will lag behind car electrification, but how long is uncertain. Early adopters will pay mega bucks, those who wait a while less premium, then e it EV, hydrogen, biofuel or whatever will become normal and sticking with the old ICE tech will become the expensive option. Cars quickly became cheaper than horses, digital cheaper than film, email less than fax etc