This doesn't work so well as to warrant an 'eye-roll' for a large portion of the world, where it would be ridiculous to expect people to be riding ebikes long distances, for half the year or more. In my city, people would think you were insane if you tried riding more than than a few Kms with any regularity during the winter, since it often hits -45 C (-49 f), generally with significant snow and slush on the ground. It's also not exactly trivial to make such a huge change to layouts of cities' traffic flows.
Edit:
As a point of illustration that I'm not overstating the issue, my city actually has a thriving e/bike rental market for 5-6 months/year and for the other part of the year, the rentals literally disappear and you can't find a single one until part way through spring season.
Aside from the triviality that the cities with highest rates of cycle commuting all have snowy winters (Denmark, Sweden, Norway), a city where people regularly commute in -45C will really not matter if people are walk+transit or cycling. -45C is not normal.
If you're riding at any decent speed, say 20 mph (32kph), think about the additional windchill that adds: -30C becomes ~-46C, if you're blessed enough to not have existing cross or head winds.
Base -30C temp is pretty normal here during the winter (3+ weeks worth before winter even started this year). Granted, in my city at least, we would have to do a much better job clearing/sanding your proposed bike roads than we do our regular roads to maintain that speed on a bike with any sort of safety. In any case, it's a helluva lot easier/more comfortable and less risky to bundle up and trundle to the train/bus station, than to risk additional frostbite from that windchill or wipeouts due to reduced stability of bikes on ice for any significant time. Again, assuming you could convince everyone else who has money for a car to abandon their cars and convert enough roads to dedicated bikeways, and build the infrastructure to safely store a bunch of $3,000-$7,000 ebikes.
Beyond all that, ebikes don't solve a lot of problems if you have a family of any significant size. If I have to buy, maintain, and secure 5 ebikes (and get my kids good with and prepped for riding in the cold and snow), public transit or even a car start looking much, much better.
I realize that most people don't live as far north as I do, but there are many millions who do and my whole point was that it's not eye rollingly obvious that ebikes are the immediate solution for everyone.
Edit: As a point of illustration that I'm not overstating the issue, my city actually has a thriving e/bike rental market for 5-6 months/year and for the other part of the year, the rentals literally disappear and you can't find a single one until part way through spring season.