Do consumer standard lithium-ion batteries exist yet? (Aside from 18650s, which might barely count).

It's 2024; how come companies like Sony, Panasonic, Energizer and Duracell haven't jumped on offering one or two standard replaceable lithium-ion cells, with integrated circuit protection and slim enough for modern consumer electronics, that people can buy off-the-shelf in drug stores? Many devices are still running on alkaline batteries these days, like smoke detectors and kitchen scales.

It didn't take that long in the old days for standards like AA and AAA batteries to hit the market, and they didn't worry too much about applying them to new chemistries with differing voltages. And with efficient DC-DC converters that are cheap enough to introduce into consumer electronics, battery voltage hardly even matters that much nowadays.