Your baseball card became worth more because more of them got lost or destroyed over time so it got more rare.

Assumption. That can happen because the athlete has a very good season, or even becomes famous/infamous for an unrelated reason.

In other words, you're assuming it's because supply went down, but it can also be that demand went up. Or a combination.

But that's beside the point, which is that its value changing has zero impact on what's in others' wallets. Because it's a price tag. Not an amount of actual money.