You don't mention how much your system costs (not that it's particularly important), but it's clearly less than $150K and situated in a custom built room - at some point in the upgrade process, you hit that knee in the curve where improvements are going to be more and more expensive. Since you can get a large majority of your CDs for between 8 and 13 dollars, you can get significant amounts of music for the same money as one of these expensive upgrades. Earlier on, it might have been 100 CDs for the same price as a very significant upgrade (relative to the quality of the system then). Now, it's probably 500 or a 1000 CDs. That makes a fairly compelling case for buying music and letting the system be.
Not caring for classical keeps the system cost down, as well. I like Rock, Blues, Jazz and several other genres, but I rarely listen to classical.
Finally, I'm guessing everybody who says they're at that point of the system being more than sufficient for most of their music collection has a system and a music collection that basically everybody they know believes is "over the top" - you're probably the most hard-core audiophile any of your friends know. And yet, there's something about getting to the point where the gear is sufficient and the showpiece CDs or LPs become uninteresting to listen to, that makes you question whether you're a "true" audiophile. Once again, it's easier (and cheaper!) to conclude that you don't much care. -Kirk