There's an age requirement to electric cycling (14) so not very accessible to all. You also have to consider the extra maintenance of these bikes as well as disposure of the batteries when it comes to the end of its life.
I agree, there is a lack of investment in cycling infrastructure but the problem is, that the demand is not there. Many people are already used to commuting by car or train, and in some cases, walking and taking the bus but when they stack up, the percentage of people who bike is pretty low. There is already the social stigma that cycling is a dangerous sport to take up with scare stories going about car to bike fatalities passed around, it could probably take a few generations to start encouraging people to cycle to the shop, let alone to work.
You could say, 'build the cycle paths and they will come', but the thing is, will they come?
I'm not really advocating electric bikes for kids, or indeed anyone. Most kids should be able to get up hills with a normal bike with gears. I've got an electric bike but I'm in my 40s and do long trips sometimes. But even I don't really need one even though I'm not particularly fit and a bit overweight. I have one mainly because it is fun having one.
No demand? There is plenty of demand for transport, and there are plenty of trips less than 2 miles, easily cycling distance. People aren't cycling because they perceive it as too dangerous. The Dutch also thought cycling was too dangerous until the 70s.
See, British people can't help coming up with excuses why things can't be be done, and I'm not just talking about cycling. British people think they are living in the best country in the world but when evidence is presented showing the contrary they are not interested in doing anything about it.