"When off there's no additional rolling resistance over a normal bike."
Until you get to a hill where the added weight of the e system can't be ignored and not a liability on a normal bike of like kind. The type/terrain of gravel riding I do on my 45lb. bike would have you reaching for the on button pretty quick if you tried to use your bike un-assisted. I wouldn't recommend your tire selection either as you would spend all day fixing flats as well.
"Coasting I've caught and could have passed a friend who annually rides the paris roubaix cycling race."
See the above reference to weight and Newton's Laws of Physics as pertaining to:
Objects with greater mass have more inertia
I have regen on my DD hub road bikes and I am having a hard time following your logic there? The regen function may not add much back into the battery charge but it is very good as a braking aid in general which saves on pad life quite a bit I have found. In fact when I think about slowing down my regen button is the first thing I go for and apply the brakes as necessary while keeping it down. One thing it does regarding the above is that when rolling downhill with no motor use necessary to keep speed in check I use the regen and depending on the grade and desired speed, I don't like to go much over 30, is very effective at keeping to that speed without using any brakes at all. Any charge back into the battery, generally 5% over 40 miles and 500wh's, is gravy. Regen is generally only available on DD hubs but the new Gmac hubs from Grin are geared and they have worked their magic getting them to provide regen as well as being able to provide for freewheeling using only a small amount of energy.
In addition to torque sensing PAS I also have an all out throttle on all my bikes that yes does come in handy for masking the weight of my bikes if having to push and I use it with joy. There really is no effect on the rolling though when I am off the bike and without the cranks turning the bike is only riding on the hub bearings. I know it came in handy on a recent ride having to work my way through this unridable section:
This is not to ignore the other part of Newton's 1st law:
Bicycles have been fighting this battle for years. It is well known that a lighter bike will handle better if compared apples to oranges. I personally have come to grips with it and actually like the planted feeling, especially on gravel, as the bike isn't as apt to deflect around on the chunkier sections.
This of course also pertains to brakes and a heavier bike will need better ones which are readily available and should be considered on any eBike in order to be sufficient for the overall weight of the bike and rider and expected speed/terrain to be able to stop in a reasonable distance safely.
There is alot of focus on the low power/low wh battery type bikes that allow for a lighter overall weight currently and it will work for some but not all potential eBikers. One is no worse than the other as long as the rider is happy with their decision and it works for their needs.