I got one for ~$700 with that (though Tourney, not Altus). The tradeoff however was power (it's 250w) and size (plus build quality, probably... also, no suspension or ignition) but it does work. I've tried an XP 2.0 so I do have some frame of reference, it still works for me.

I wonder if I'd like an even smaller bike (currently already 20" wheels, somewhat short wheelbase, 45lbs), though I might just want a lighter bike (which would cost more). Well I would wonder, but from what I've seen I'd need to buy something used (and it's more of a UK thing) to get a small (non-electric) bike for under $700. Sometimes just the frames for those cost over that. Also, searching for this size of bike is difficult (results give small motorized things (even w/bicycle), bike models, clown bikes (no gears)).

Right, you're better off building your own.

Ar one time that was true here, but anymore used cars have become as expensive as a new car.

I bought and sold my kawasaki ZR7 for around ~3k, half of what even some of the cheapest road legal E-Bike costs, more like a third of the price if you look at average.

The inclusion of “even some of the cheapest” here confuses me. And the idea that 3k is a third of the AVERAGE price?

Some of the cheapest from specific brands, maybe. A Trek eBike will put you out a significant chunk of cash, sure.

But the cheapest eBikes are not $6k, and the average eBike is not $9k.

My Aventon Level.2, a class 3 eBike which will pedal assist up to 28mph/45kph and which I regularly ride on roads, was a little under $1800. Plus $40ish dollars for the oval 52T chainring so I can actually sustain that 28mph. And Aventons are sort of middle-of-the-road, price-wise. Not cheap, not excessively expensive.