You’re right, and that’s sad. (Umm, that 14500s are dead-ended, not that you’re right.)
14500s are not AA drop-ins, ’cause a lot of things won’t take well to being hit with 4V when they’re expecting 1.5V. Certainly not with series-connected cells. Motors (shavers, etc.) will run obscenely fast, hotwire bulbs will have a short fraction of the lifetime, Si-based goodies can let out the Magic Smoke™, all sorts of bad things can happen if the doodad in question isn’t designed to tolerate Li cells.
Joe Idiot who buys 14500s and pops everything he puts them in, will badmouth 14500s like crazy. WallyWorld isn’t stoopit enough to sell 14500s because of all the Joe Idiots running around loose. At least 18650s won’t fit into anything that’s not designed for them. 14500s? The Silent Killer of AA-based electronics…
Now, maybe flat-top 14500s would sell, doodads can be designed to have built-in protection that only cells with a nipple on top would make contact. That might work. But button-top 14500s are a specialty item, and no mfr is going to put too much effort into them except for niche markets like flashlights and… ummm… whatever else might use 14500s without damage.