Did you mean reduced supply?
The supply doesn't get reduced if you loss access to your coins due to misplaced private keys or mnemonic phrases. Whether those coins circulate or not, they are still there.
But when the coin become inaccessible it automatically goes out of circulation and the total supply becomes limited, which translates into reduction in the circulating amount so also the same with other coins that offer periodic burns just like ethereum 2.0 forks where some percentage of the fees get burned to reduce the amount of supply.
I remember reading a post sometime ago about the burning process of altcoins, more precisely the burning process in centralized systems. The idea is to positively affect the price by reducing the supply. But that only works if there is already a significant demand. A shitcoin with no traffic remains a shitcoin with no traffic even if you remove 10%, 20%, or 50% from its supply. For tokens like Ethereum, it probably has some effect.
The post I mentioned above, said that in centralized blockchains, even burned coins can be retrieved. The team/developers/foundation/whatever just changes the rules if they want to. They can do that because they are centralized, and they don't need the support of the entire economy (miners, nodes, exchanges, users...).
