Buyers are aware they exist and registration isn't a problem. Ability to repair is another big problem / question mark.

> The heaviest ones seem like the same weight as a 600cc or 1000cc crotch rocket - am I missing something big?

Livewire One is 560 lb! Energica Ego was 570! 600s and liter bikes aren't anywhere close to that -- low 400s lb for 600s, and 430-440 lb for a liter bike.