Same story as with hard drive based audio players. I've been using one (if I remember correctly) from Creative long before iPod materialized. All was quiet but suddenly as iPod came it was of course called revolution.
Apple is very good at maximizing "consumer satisfaction". This means giving consumer the best deal for their money considering as many of the consumer needs as feasible. Other brands ignore a lot of these needs and then they wonder why people don't buy their products when, on some details, they are much better than Apple at a lower price.
A product isn’t merely checking some boxes. Checking the “has hard drive” box doesn’t make any it an iPod.
Having many gigabytes of audio was a big step.
The first "box" I used to check when buying things like that is that PC sees it as a hard drive to which I can copy files. That horror they called iTunes would not be let anywhere close to my computers.
But I remember that ipod was awesome (comparing with the other players with shitty controls and sticky buttons). I hated apple products at the time (religion) but I was amazed by the quality and UI of ipod and the quality of ipad (took me and my kids many attempts and years to actually kill it).
I don't think any other product amazed me that much since then.
When iPhone came out, the responsive UI was something I'd wanted for the past several years worth of Palm and HTC phones. But I couldn't get one because I'd have to give up things I used daily - like 3rd party apps, 3G data, turn-by-turn navigation, MMS (which was still a big deal before the prevalence of IP-based mobile IM platforms), multitasking, live streaming radio, and even "crazy" features like copy/paste and custom wallpapers/alert sounds.
iPhone did a few things very well, but it took a while to catch up on a lot of the common functionality of those older smartphones. Thankfully Apple did add those features over time. And other smartphones gained more responsive UI. Now we have more options than ever, with even the cheapest bargain device performing better than anything available in 2007.