The notion that because people are on an e-bike they are going to be going at 30 mph is silly and one can spend 10 minutes at a bike path and simply observe to know this is not the case. A Class III bike only provides pedal assistance and I can go just as fast on a non e-bike. What I do see are people with e-bikes that can make it up a hill and not have to dismount and walk to the top. They can be of average fitness and enjoy bicycling.
On the bike path near my house the primary problem encounters are with pedestrians with strollers and dogs (often off leash) and ground squirrels. I avoid one particular section that has a high density of groups who will block the bike path as they stand and chat. They never think that they should get off the paved path to chat.
REI and others sell good e-bikes for less than $2500. That is what I spent for my standard CF road bike in 2000. We bought a small plug-in hybrid and paid $55,000 and a 1/2 ton pickup that cost $65,000 so a $2500 e-bike is not excessively expensive. For commuters having their car sit at home saves on gas, saves on tire wear, saves on auto insurance, saves on parking fees, and that easily offsets the price of the e-bike.