We have this audiobook player for children in my country. That works by buying those little figures and if you place them on the player, the audiobook plays. I think that a system like that for "adult music" would be awesome. Buy some little figures and art pieces by your favorite band, display them on a shelf and use them to play music? Yeah, that would be awesome

Nintendo sells essentially a SD card variant in a case for the swtich. So you're not far off :)

at least being on a thumb drive would be more durable, compact, and have faster read time.

Actualy, thumb drive flash is the lowest quality, cheapest one (the yield thing, the outer parts of the waver). Do not expect your data to keep longer than a few hours weeks.

Edit:

Because that's how yields work, defective areas get firmware-disabled in the factory. Lower quality has only more of them, with less strict quality requirements to count as ok.

To add, it's a gamble; most are ok, some get data corruption on write, some after weeks. The "cheap" part is, because they aren't expected to last more than a few TBW.

A system of organization would be invented. Idk maybe a wooden stepped board with USB sized holes that you store/display your collection in, just to use the first idea I pull directly from ass. Actually make it silicone for the grippy, already improving it, then sell the wood as a fancier looking one, and inlay a few with idk brass or something for a "pro" version, boom, marketing.

Realistically the connector would have been proprietary, but I can see a world where we got cartridges that came in little cases like the games for nintendo ds or switch.