Spoiler: I had like 29 pieces of sushi for under $18.
Spoiler: that was too much sushi. I walked it off for 45 minutes and still felt bloated.
The place was Sushiro, apparently a chain. People were waiting but as a solitary person I got seated at the counter right away, in front of the belt. Also had a touchscreen, with English option, for ordering stuff if I wanted, or calling someone at the end to tally up. Three tiers of plates: 100 yen, 150 yen, and I never saw the last one so whatever. 100 yen for a pair of tamago, but also for a pair of tuna. I think a plate of 3 different pieces of salmon was 150. 2 pieces of eel were I think 100, one dark piece of presumably 'better' eel was 150. I ended up having 11 100 yen plates and 4 150 yen plates. Apart from the egg plate, all were fishy (or meaty: one seemed to be beef nigiri.) And decent size pieces, not tiny, like a couple of my thumb widths in width. Recall that 100 yen is basically a dollar.
I'm not that unfamiliar with kaitenzushi being cheap: a floating place in Portland Oregon had $1 for egg and maybe $3 for salmon, when in restaurants elsewhere it would often be $3-4 just for egg. But still, dang!
Some other things took me a while to figure out. Hand wipes were hiding above my head. There's a jar of green tea powder -- like matcha, but presumably not actually high quality matcha -- to mix with hot water from a tap. No little soy sauce/wasabi mixing tray, I had to re-use an empty plate. Jar of pickled ginger and bottles of soy sauce at my spot, but little wasabi packets go by in a bowl on the belt. Not to be confused with the little packets of red pepper going by in a bowl on the belt. Fortunately I now know to look for wasabi (in hiragana).
In other things... I was walking along a main street, noting how dead it was. I saw the tall apartment buildings, and wondered how much ground level retail there was, and tried to pay more attention. It's mixed: many just have a lobby, or some private parking (that was actually for a fairly short and setback row of apartments.) Others do have businesses, restaurants or even paid public parking! But yeah, it could be more ubiquitous, especially given that you'd think some 12 story building provides lots of its own customers.
See the DW comments at https://mindstalk.dreamwidth.org/528575.html#comments