I used to play Magic on the side of my main game, SWCCG (star wars customizable card game), which I was a grandmaster (2000+ ELO), back to back state champ and top 100 in the world... Then WOTC acquired the license to make star wars card games and made their own (absolute garbage) star wars game and I retired. I still have a bunch of my MTG cards, and I've owned some incredibly expensive cards that I (unfortunately) sold around 01' (Mox pearl, Time Walk, Candelabra of Tawnos, to name a few)... most of the valuable cards I still have fall in the 10-100$ range at best, merely due to the age and time period I played.
Despite having not played for around 15 years, a guy at my last job talked about how awesome he was at magic and when I mentioned I used to play, he told me how he would own me... I told him to bring his cards in. We played a few games on a slow work day, and I handed him his ass with his own decks 5 out of 6 games with cards and abilities I had never seen, and was learning as I was drawing them. It had to have been extra embarrassing losing to someone that's asking "what does this do?"