I dunno man-5 years is a lifetime in the electronics market. If the push to get petroleum pollution off of lakes takes hold things will happen fast. Remember a few decades back when they started talking about unleaded gas and people thought it was quaint but didn't take it seriously.
One of the big advantages of electric on lakes is that there is a finite perimeter so getting back to your start point shouldn't be too difficult. Not so true on huge reservoirs but we have to assume some planning skills on the part of the operator. Having had gas powered outboards before I like the idea of quiet non-smelly electric power. I also like all of the battery powered stuff like weed whackers, chain saws, leaf blowers, lawn mowers, camping stoves and will be adding a battery powered snow blower before winter. It all improves every year. Yeah, early adapters are paying through the nose right now as the development curve is in the steepest part of it's ascent but that will level out when the product becomes mainstream.
Before I saw this thread this morning I was wondering what will be done with millions of vehicles on this planet when gas is no longer available. What is your guess? Perhaps all of the cute utes and SUV's would make good greenhouses with all of their windows, doors and hatches. Fill them with dirt and plant crops and since they have wheels tow them around to be in the best sunlight. But how do we tow them-a brace of oxen?