Quote from Mtgthewary »And how often we do this? Yes you can say money is not important, but you can tell this after another ban guys like you and me loosing a lot of money.
It's an open question as to how many bans have actually resulted in devaluation of card prices over the long run. The banned card certainly loses value with few exceptions, but the overall deck might retain value or increase through natural factors unrelated to the ban. One could easily compare historical price data from the time of the ban to the deck's value today. For instance, here are some May 2015 deck prices:
Amulet Bloom was about $575 in May 2015. Wizards banned Bloom in early 2016. Today, MTGGoldfish lists it in the $790 +/- range. Obviously, other factors have increased card value such as format popularity, scarcity, EDH demand, etc., but overall the parcel of Amulet Bloom cards has increased 35%+ since 2015. I suspected this would also be true for URx Twin cards, notably Tarns and Snapcaster. In fact, a cursory glance does suggest this to be true: UR Twin went for about $1,000 in May 2015 and the same parcel of cards goes for about $1,300 +/- today; here's Sam Pardee's old GP Charlotte UR Twin and some other decks for comparison (https://www.mtggoldfish.com/deck/296690#paper).
It's definitely possible that if the cards had gone unbanned, the overall deck would have increased in value even more than it increased naturally. It's also possible that there was a short-term loss in value in the 1-2 year timeframe. But at least in the Twin and Bloom cases, banned decks don't appear to lose value over time in the Modern long run.