https://duckduckgo.com/?q=boombox+on+shoulder&iar=images&iax...
Storing your media locally is fine, but you only have it when you're physically at your machine. To go portable you have to manage syncing files to an external device. Now you've got two libraries to manage.
Yes, we lived with this kind of thing since digital music existed, but it was a pain then and it's a pain now. Keeping one centralized library that any device can play from means less effort required to maintain the library.
Plus I can play my music in the car from my phone and never have to hear an annoying radio ad again.
It's far bigger of a pain for me to deal with streaming. I don't have an unlimited data plan so streaming on the go is right out.
Just copying whatever music I want to listen to on the go and playing it back locally is far simpler and easier than dealing with Plex/Jellyfin, hosting a server, managing a VPN, and all the other sysadmin nonsense.
Vinyl has outsold CD's in dollar terms for years now, and for the last several has sold more in raw units as well.
I was off by a year or two. Point still stands.
https://www.statista.com/chart/12950/cd-sales-in-the-us/
CD sales have declined, yes, but the perception is a bit skewed because CD sales dwarfed vinyl even in its best years.
Many indie labels that I enjoy discovering about, sell CDs after their concerts.
It is quite alive.
Whether you grab your MP3 off of local storage (eg: HDD), off of LAN storage (eg: NAS), or off of WAN storage (eg: Youtube), you're streaming.