public parking spots are extremely cheap to build - basically involves pouring asphalt or concrete
Uh no. It involves leveling and lowering the site, backfilling with a proper bed, laying asphalt or concrete (asphalt if you're smart, due to its repairability) and then typically also doing some landscaping. There's curbing, there's permitting, there's drainage which you've ignored completely and which I'm glossing over which might cost as much as laying the surface itself... Adding some conduit, wiring (which can be Aluminum since it's just going to lie there) and some meters does significantly add to the cost of the whole thing, but not overwhelmingly as you seem to believe. Also, the parking lot becomes a profit center rather than a drain which is simply necessary to do business. People will be paying for charging. You'll be charging them a premium for the electricity, and they'll be happy to pay for the convenience — it'll still be markedly cheaper than driving on gasoline. It's actually a win for everyone, and you start with just a few spaces near the existing electrical services, keeping initial costs down. The demand for full lots isn't there yet.