Submarines are electric have been in operation since the turn of the century. The first electric sub launched in 1888. So the technology is there. But, the point about it taking decades is probably correct in terms of the market. It's just not likely that there will be any real market for electric boats among power boat enthusiasts for decades. It'll be about that time that gas is $20 a gallon. The sailboat community will be much faster to adopt electric.
An electric performance boat would just make me go a big rubbery one.