Is eneloop not still very much a thing? Maybe not the brand, but the technology. The vast, vast majority of consumer devices using standardized battery sizes are AA or AAA, and that means NiMH. To go lithium means 18650, and I don't really see much of that happening outside flashlights and other niche products.
Sure, if a device uses the form factor, then eneloop or the same approach by a different brand are even more ahead of pre-eneloop NiMH than they used to be: all the high-current use cases that were the weak spot of eneloop have long migrated to lithium-based.
But AA and AAA are increasingly rare not only because of price but also because of the ubiquity of USB charging, and because of the way the powerbanks that USB charging enabled weakened the "carrying spares" argument for AA a lot.
In essence: yes, the vast majority of consumer devices using standardized battery sizes continue to be AA or AAA (if we can agree in ignoring the ubiquitous CR2032). But costumer devices that use interchangeable standard size batteries have become super niche, at least outside a few fields where you expect years on a set of batteries. To go lithium means going fixed battery (unless you identify with the performance flashlight subculture, again something I very much agree with)
There are many companies making rechargeable lithium batteries in AA and AAA form factors. I have a few dozen I use for my door lock and Xbox controllers.
Lithium mostly exists as pouch cells in consumer devices, standardized batteries in general are rare. AA/AAA is mostly used on extremely cheap stuff, or stuff that one expects to last 5 years or more so nobody cares about recharging.
I hope we eventually get a consumer friendly standard for lithium though. It could be so much better than cylindrical cells, we could have all our cheap gadgets using micro versions of the power tool slide on shoe concept or something. Kinda unbelievable the ISO isn't trying to standardize prismatic type cells.
Form factor smaller than 1865 with energy dense formula is rare. Chinese made LFP but only a handful of mfgs make them anymore. So size doesn't matter, but it basically matters :D
Nothing except flashlights and yard lights seem to use them either. Probably because they're not exactly safe enough for frequent swapping applications, consumers will drop them on their tin foil crack smoking rig and make a fire or something.
