Hmm. I hold quite a few of my decks sacred, but for the most part I have far less valuable cards than you.
Maybe, but I can't really take credit for that. I didn't buy that many cards when I was younger, but I started a long time ago and kept my cards, so some of them that weren't expensive would later become expensive. I have two younger brothers that at different points had small collections and gave them to me. I pooled my cards with my best friend's cards because we wanted to collaborate and build Legacy decks. I took some of my decks apart before that, but I think he was the one to dismantle most of my old decks. I think he bought a couple of other people out of their collections too. I was busy with other things, so he did our deckbuilding for those years, I just occasionally played with what he'd come up with. He also sold or traded some of my cards to acquire cards that would better suit Legacy at the time, which I regretted somewhat for a while after I found out (it was a mixed bag: he traded away all but one of my Morphlings before they lost too much of their appeal as the game evolved, but he also sold all of my Sliver Queens, which I wanted because I really liked slivers conceptually, not because I wanted to use them in a tournament deck). We were roommates for a year or so and we'd kept communal card collection in my room, so I moved it with my things when we both left, and he declared the cards to be mine, even though he'd clearly put a lot into the collection over the years. I've bought some cards since then to further develop decks I'm interested in, but a whole lot of my "valuable" cards were basically inherited.
I do sometimes wish I still had my old decks. I kept a blue bounce-based deck for almost ten years, but it's gone. I played various Necropotence-based decks more than any other type of deck I've ever had, but I no longer have a single Necro deck. There were others. I almost always had some Pestilence deck, which was black/white, black/red, and monoblack at various stages. I remember Septic Tank (a Megrim deck that I named after, well, it's a long story), a High Tide deck, a red green combo-filled quasi-aggro deck, a Rabid Wombat deck, monoblue control, black/red land destruction, various Yawgmoth's Bargain combo decks, a Hecatomb deck, a Land's Edge deck, some blue aggro-control thing based around tapping things, monobrown rampy shenanigans, a poison-counter deck, a sort of proto-Esper Highlander deck back before Highlander formats were even a thing outside Seattle, and yeah, at some point I must have thought that I had several decks that I'd keep around "permanently." The only ones that have survived since the last time I moved have been Burn and a Fluctuator deck. The Burn deck is at least 13 years old. The Fluctuator deck is probably 8 or 9 years old, but I'd totally take it apart if I wanted the cards for something else. However, that seems unlikely. I'm not exactly desperate to include Bloated Toad in most of my decks. So with that in mind, I chose the option for 1 to 3. It's either just Burn, or it's Burn and Fluctuator.
I just noticed that there's no option to choose 0. I wonder if that fits anyone here...