this needs another polymer-based ROM format - if we can call CDROM/DVD that. but those require a moving-parts device, and it's optical. anything else requires silicon. microSD cards are cheap now, many-Gig, tiny, how many wavs or mp3 or flac can you fit on that, a lot with 32GB.
it's the player device, if you don't want to use your phone. and that needs a decent Line Out, rechargeable, USB C for power and transfer. (phones use shitloads of power... recharge every 24-48hrs? don't need that with a dedicated player unit surely)
and then distribution sites have to get it together to allow bulk downloads of curated material. loads of mixes, playlists, up there. what about 'charts'? does bandcamp have charts and playlists, per (genre, eek)? i would actively go to that if it existed for various forms of techno/electro/industrial etc.
and buy your music by the kilo (or gig). i used to filecrawl in internet cafes with soulseek: dump a couple of gig on their hard drive, as 'shared files', click on a load of stuff i was interested in, do my internet stuff, collect my harvest in that time using their decent connection, pull out the pendrive and see what i had when i got home. primitive (and i was paying the internet caff 1eu/hr, cheap entertainment in a boring place) but productive. it was a fun way to search for interesting audio. (and i'd collect a gig of freeware VSTi's, shared sample collections, etc. in the process)