Oh How the Mighty Have Fallen
It’s always interesting to see how hard a card falls come rotation, and for those who are unaware we have three great examples here. Bonfire of the Damned peaked at $46, but guess how much it costs me right now on Amazon? As little as $5…. What about the big bad Thragtusk that absolutely ran standard and peajed at $24? A whole $2.43… You get the idea.
For all the new players out there, the rotation is when standard changes which sets it includes. It always includes the two most recent blocks (Theros, Born of the Gods, & Journey into Nyx makes up a block) along with a Core Set or two. But when it rotates an entire block and core set lose their standard demand, so the castle comes tumbling down as no one needs these cards anymore. Which is why I’m glad to have sold my Thragtusks for $15, because now that’ll get me more than a playset (even though EDH only needs 1). It is also why people sell their cards as far before rotation as possible, to try to avoid losing too much value to the crash.
While I totally agree with everything that the OP said, I have always employed a strict policy of keeping a playset of certain cards post rotation. I was burned pretty bad in the days of the original Ravnica block and Lorwyn block. I looked back at how many bitterblossoms, thoughtsieze, dark confidants, glimpse the unthinkables went through my hands and it made me sick. I keep my bonfires, I keep my swagtusk combo, and I keep my Geists of St.Traft, my fetch lands, etc…because I refuse to be left behind when Modern causes a real spike and these cards are worth 5x their original value.
That said, if you speculate in MtG futures for the sole purpose of making profit, then what I just said may not be for you. I just really hate when I need 4 Bobs for my mono black aggro and I have to pay $75.