I didn't say they were street legal, but it's not hard to find a 30mph capable kit:

https://www.electricbike.com/cheap-electric-bike/ http://myelectricbikemotor.com/category/30mph/ https://www.amazon.com/Folding-Electric-Bike-Adults-Enduranc...

I haven't seen it in the comments yet, but it will only be a matter of time before these ebikes will need to be registered, have a number plate, and can receive speeding tickets.

Right now there is no way to identify a speeding bicycle, no matter how fast its going. You could be doing 50 in a 40 zone and there is no way to issue a fine.

Bikes are frequently pulled over for speeding. I don’t know where you live, but cops like to set up bicycle stings at the bottom of hills in the Bay Area. Not to mention giving out tickets for things like missing bike bells. Oh, and if you don’t register your bike with the police good luck having them help with recovery.

I have a friend that got a speeding ticket on the back side of the Marin Headlands - it was a moving violation, he went to driving school to keep it off his record.

Where in the Bay Area are bells required? I've never heard of police there ever enforcing equipment requirements, not even lights at night.

That depends on the jurisdiction. In MA, it’s a point of ambiguity, but I think that’s resolved in favor of e-bikes being treated as mopeds today (with a max of 30mph): https://www.massbike.org/ebikes