I found these products and force-fed management software absolutely horrid. I didn't even want iTunes on the family computers, or a dependency on Windows. I maintained a couple of old desktops for my siblings, for very basic Linux desktop appropriate tasks, as in browsing and OpenOffice (I didn't believe in Linux on the desktop and I still don't, for my own use).
So, an mp3 player that didn't let me transfer and/or play my meticulously organized mp3 and/or FLAC collection was just plain cancer in my opinion.
As a teenage "family sysadmin" I made sure everyone got USB mass storage compatible mp3 players and used media library software like Winamp 5 or Amarok (the original branch that's currently known as clementine) for media management.
The way iTunes was intrusive is of course why it worked for ordinary folks, who didn't have a "sysadmin" like me. But iTunes was such as piece of flaming garbage it couldn't even remove dead/missing files from its media library database automatically.
It's amazing how bad iTunes remains, and I've never used it for music. I mostly like Apple's approach to things these days, now that my time is worth money. The only thing iTunes does well in my opinion is that it takes disk image backups of iOS devices, an essential part of why I now use iPhones, but that's another story.
However, the iPods/iTunes had their good points, none of which I didn't understand at the time. The iPod, if memory serves, never ever rebuilt its media database on its own. That was the job of the iTunes software, for the sake of optimization and keeping the iPod system lean, pleasant and fast (please correct me if I'm wrong).
This philosophy remains visible with Apple's Airport Wi-Fi base stations to this day. Apple base stations do require a proprietary Windows or Mac utility, which was a non-starter for 19-year-old me. But the Airport utility still basically uploads conf files to the base stations, which run pretty nice and slimmed down NetBSD based firmware.
In retrospect, it was smart of Apple not to do stupid bullshit like vulnerable and memory bloating web interfaces on base stations. Those Airport base stations are solid, and by the way, a decade-old models are still supported with updates. The listening daemons available on Airports, Airplay, Apple's lossless (!) music streaming, since 2004 (!), and printer sharing, never had to compete for RAM.
Anyways, at the time, in the early-mid 00s, the only benefit I saw in being in the iPod ecosystem was early adoption and universal support of AAC as the go-to lossy codec. Fiddling with those VBR presets for the Lame encoder was and remains the only way to get decent sounding mp3s, without maxing out the codec at 320 kbps. A maxed out bitrate would have been just wasteful on a my tight budget in 2004. I had no money to spend on storage, so I wanted my music collection near-transparent mp3 VBR files with average bitrates around 200 kbps. My equipment was just worse, so I could live with those bitrates. Good headphones used to cost money and portables had pretty modest headphone output quality.
Btw, features like seeking and correct time displays for VBR mp3 was far from perfectly supported at the time. Amazingly, this still remains the case, which, by the way, is one of the reasons why podcasts are almost universally CBR mp3, even when produced or prepared for distribution by people who know what they're doing.
Flash storage was expensive at the time. So, I used CD-RWs with mp3 compatible portable CD players, mostly from Sony. It was risk management on my part - I didn't want a fancy HDD based mp3 player because I couldn't afford to replace it if I ever dropped the damned thing.
And 512 megs of non-replaceable flash storage was just too tight for a vacation, which is what cheap small mp3 players provided. Eventually, mp3 players were good enough though. My last flash based mp3 player before my first smartphone was a Sandisk Sansa Fuze, it supported removable microSDHC, I think, and even the Vorbis and FLAC codecs.
I got into Mac with the late 2008, first pre-pro unibody Macbook, because I worked a service desk gig at the time at the time, and consequently didn't want to even see Windows in my spare time. I also wanted Unix on the desktop, which is a problem Apple still solves, although at a premium.
To be honest, I don't I think I ever would've switched to iPhone due to the missing USB mass storage mode if Spotify hadn't completely taken over my day-to-day music listening. But what pushed me from Androids early was the lack of even security updates on newish flagship phones back in 2011. I considered iOS 5 with music through Spotify good enough, and I've never looked back since.