iTunes worked because it was essentially a spreadsheet where you could dump all your music and have it categorized by the basics of searchability: artist name, song name, album name, year, and so forth.
However, while iTunes excelled in organizing metadata, it wasn't the place you searched for new music. Niche MP3 stores like Bandcamp and Boomkat, music blogs like Stereogum, and SoundCloud And YouTube we're the go-to online record shops.
The music ecosystem is still fractured to this day. You're never going to hear a track and play it back all in the same place. You platform-shift, finding a tune on YouTube but end up playing it back on Spotify where you keep your entire collection organized, or aspects of it.
The irony of paying for an all you can eat streaming subscription service is that you're renting the music while you at least owned your MP3s. The same can be said for Kindle books. Unless you own physical or the digital source file, you own nothing.
While music discovery is site agnostic — it doesn't matter where or how you dig up new tracks — music collecting is anything but perfect. There is still no one-way to store and organize your collection. All of these MP3s of bootleg recordings and live shows you gathered back in the day won’t have a home until you spend hours or days uploading them into a cloud service.
The process of music discovery, collecting, and listening happens on an array of applications and a mix of file types. If you're passionate about crate-digging, that's just the way it is.