> So I need to purchase the MP3's in order to do this?
Aye, aye.
> Then I need to spend time on other web sites for music discovery?
One cost of cultivating tastes, as opposed to being fed by a recommendation algorithm, is the risk of possibly hearing music you might not like, as well as the time required spent doing so.
There are open-source music recommendation algorithms but having survived radio payola I consider that approach a step backward.
> This would work if you almost never venture outside of your existing music catalog.
I favor bulk music downloads (more than I could ever listen to) and randomized playlists, but then, I may have a higher tolerance for my tastes not being pandered to.
> I can't even contemplate pirating all these songs,
Seems to me that you are doing precisely that.
> since I find that morally wrong because the paid services (for music) are decently affordable and provide good value.
Wait, you find it morally wrong to infringe copyright (a specious proposition in any case) because the paid services are affordable? What is the price point that makes piracy moral, then?