Android phones, too, can play whatever music files you can load them up with. Now, truth be told, if any of that applies to you, you still don't need an MP3 player - your iPhone can still sync music files from iTunes (on Windows) or the Apple Music app (on Mac), and it probably has more storage space than your old iPod ever did.
Maybe you've got one too many subscriptions already, so why pay for one more when you already have a music library of thousands of MP3 files sitting on your hard drive? Some of you, meanwhile, have meticulously crafted iTunes playlists, like mix tapes of old, that you don't want to recreate or transfer to another service, or rare, one-off live tracks that don't exist on mainstream services. And the tracks are downloadable, too, so you can listen to your music even when you leave a Wi-Fi or cellular coverage area. You pay your $5 to $10 a month, and you get access to nearly every popular song ever recorded. Who needs a standalone MP3 player in 2022? In my opinion, the answer is 'almost no one.' Any iPhone or Android phone is an audio player that works with subscription music apps like Spotify, Apple Music, Tidal, Amazon Music or YouTube Music.