No, Winamp was the last example of broadly used "appliance" software that wasn't inextricably tied into a megacorp's business model. iTunes and Windows Media Player were both bloated because of the e-store baked into the back end.
iTunes, when tied to a "megacorp's business model," still suffered from piss-poor UI. Take, for example, the "LCD" display at the top of the UI that was even depicted as having a transparent cover over it... yet had undemarcated clickable controls in it (which you were likely to never discover).
So I don't see the relationship between good or bad UI and business models in this case.
It wasn’t until two years later that the store was integrated as part of an update.
Although there was an (Carbon?) OS X version for a while, Winamp was Windows-only from what I knew, so my opinion of it was always coloured by having to use Windows to interact with it, although I used CrossOver on Mac and Mint as well.