This started as a great topic but has gotten a bit off track. To address the question however, IMHO, is somewhat multi faceted. There is a definite lack of e-bike dealers and while brands of dependable e-bikes are certainly out there, prices of those bikes are quite capable of presenting some serious sticker shock. For space consideration I'm not going to address kit e-bikes despite the fact I've built two.
I live in a flat land, Florida. Little or no hills (except bridges) and LOTS of cars. Riding a bike on the hwy, bike lane or not, e-bike or not, is dangerous around here. While cars are not always courteous to bikers, bikers are not always courteous to cars and that is especially true when a group of bikes ride together. In urban areas where there are no bike lanes it's flat out dangerous to ride.
Florida basically follows federal guidelines with e-bike regs and that includes the 20MPH speed limit. This allows e-bikes to ride on sidewalks and bike paths without interference from the law but also limits riding on streets to 20MPH which you gotta admit is faster than 99.9 % of pedal bikes and for all practical purposes is fast enough. I don't think it's necessary to change the law to make e-bikes faster.
Having made these brash statements, back to the subject. E-bikes need a dealer network that encompasses communities much the same way new car dealers do. Selection, service and price are critical to auto sales and I believe to e-bike sales. If we had a dealer in my community that sold at least two brands of e-bikes, offered great warranties, provided great service including service calls, had a showroom with a good selection of bikes and accessories and had the patience to introduce newbies to the electric world I firmly believe that dealer would be successful. Unfortunately we don't which means every e-bike I see is either kit built or purchased from a distant dealer or online. This means I rarely see another e-bike.
What's amazing to me is that a lot of folks, including a couple of those in my Sunday Morning riding group, don't think twice about spending a couple of thousand dollars on a road bike but think my Pedago Interceptor is expensive. My previous e-bike, one I converted using a Crystalyte 1000 watt, 48V 20AH LiPo batteries on a beach bike frame, cost more. Was uglier, not waterproof (even a little) and didn't handle half as well. (it did go 32MPH though)
All this makes me think a dealer network with informed staff and the concept outlined above, is what it's going to take to bring e-bikes to mainstream. For at least fifteen years people have looked at my bikes and were amazed such a thing as an electric bike existed. Any community that has safe bike trails, sidewalks where bikes are allowed and bike lanes has great potential but in order for that potential to be realized there has to be a dealer willing to invest time and money in a storefront and inventory.
A little internet searching will find several dealers who offer regular scheduled e-bike rides for their customers and they post videos of the good times their customers have. It's marketing like that which will bring the e-bike market forward.
But.....I could be wrong.