Having read through this thread from start to finish, the thing that stands out clearly is that people want the bike to assist or to power them along at a speed greater than 15 MPH. I also ride an unassisted bike, probably more regularly than my Ebike, and I am reasonably fit. When cycling along level ground on my UNASSISTED bike to and from work and not competing in an event, I maintain about 15 MPH. This is the same speed to which my Ebike assists. The Ebike is a bit quicker up hills than the unassisted bike and both will do about 45 MPH down the steepest hills in my area. Overall, the Ebike is a bit quicker because of the help it gives me going up hill. If I use the unassisted bike and my wife, who hardly ever cycles and has had a full knee replacement, uses the electric bike, we more or less equal in pace when leisure cycling.
The above is the whole point of an electrically assisted bicycle as defined by the present law. It exists in order to allow someone who is not particularly fit to perform on a bicycle to a similar standard as an average fit rider. It is not intended to power a person along the level at 25 MPH + like a moped. This simply isn't what ebikes are for or what they were ever intended to be. We have moped laws for higher speeds and that includes electric mopeds if you don't like the emissions from IC engines. People have then gone on to say, "but I don't want to pay for insurance and road tax and I want to ride in cycle lanes." I don't particularly enjoy paying for road tax and insurance on my car, but it's something I have to do. It comes with car ownership in the same way that responsibility comes with moped ownership. All of this garbage about cars being able to exceed the speed limit is just that, irrelevant garbage. Cars, by definition in law, are able to do that in the same way that bicycles, by law, can do things that a car can't. They are two entirely different entities each with their own list of advantages and disadvantages. To cherry pick elements of each and then contrast them to form an argument is plain stupid.
This isn't about do-gooding or holier than thou attitudes, it's about being a responsible person. To think otherwise is an admission of having lost both the argument and a sense of moral responsibility.
No one is saying that a person can't own or use an electric bike which is capable of greater than 15 MPH under power, you can do this. But you must realise that it is no longer a "bicycle" in law and you must forego the easements in law which the compliant electrically assisted bicycle owners enjoy.
There really isn't anything clever about putting a high power motor and large capacity battery on a bike. It's easy to do. You just need an eBay account and a roll of tape. The present range of legal bikes and kits are well developed and will allow people who are unfit or have a disability to perform at a level similar to or better than the average cyclist. If you want anything more than this, that is fine, but but you have to do it intelligently and properly. You owe that to the vast majority of legal bike owners and retailers.