Good resource thanks for posting! It seems like they really went out of their way to avoid mentioning EBikes. My experience has been that for folks with disabilities EBikes are a game changer as they allow people to put in as much effort as comfortable but not go past that. I also think the section about it getting sweaty could have mentioned EBikes as a potential solution. I understand they don't want to piss off cycling purists, but I think it's important to recognize the positive impacts these new technologies have.
Finally, I get their stance on helmets and agree that helmet mandates aren't ideal. That said, I think it's disengenuous to say that helmets are useless. It's true that those studies looking at city helmet use found no difference in safety overall, but I'm not convinced that wearing a helmet wouldn't improve my personal safety. I've absolutely wrecked a helmet riding on the street, and I'm very glad it wasn't my head instead.
You're right, but I think there are some other benefits to doing away with the chain. I have an E-mountain bike and between chain stretch, chain damage, and mud I go through 2 chains per season plus a couple trail-side repairs. Also, no chain means you can optimize pedal speed/torque for each individual rider, and keep it in the ideal range all the time regardless of bike speed. Essentially it offers a much wider power band than gears and a chain. You could also optimize crank length for clearance instead of torque. The front chainring is also a big point of contact on mountain bikes, removing that could improve clearance with the right design. I'd also be interested in the regenerative braking - if I go on an Enduro ride I'm cooking my brakes on much of the downhill, regen could save those and recharge the battery at the same time. Maybe regen could even lead to a smaller battery and save some weight.
Sure there are disadvantages - weight, complexity, efficiency, probably others too. I think with time those will improve though and this just might be a viable setup for certain use cases.