Oops...missed a post there! Several reasons I guess...
1) I don't listen to the hard bop stuff as much as I used to. It was my entrance into jazz, but I'm more into newer stuff now (and, oddly, older stuff).
2) I no longer have any desire to own more and more by each artist. To use Lee Morgan as an example, if want to listen to Lee, 99% of the time I'm going to grab either the Lighthouse set, Cornbread, The Gigilo, Search for the New Land, Delightfulee or his last one. I'll probably make a one disc compilation of tunes from other discs and sell them as well. I rarely listen to the fifties stuff. I like it, but there's just too much else to choose on the shelves.
3) My newest hobby (riding, and more importantly, doing the mechanic work on my motorcycle) is soaking up quite a bit of cash, getting my shop set up, which leads to the reason everyone knows is really number one....
4) I could use the money!