What you're saying is true I think, but that's all more of a side issue for people who argue against a hard cap on supply. The main reasons some are concerned is for the future security of the chain. When block rewards run out mining will depend solely on transaction fees (= very high fees). The security of the network could fall drastically because not enough users will be transacting on-chain (too expensive and because L2s will be better for that and way cheaper) to pay miners for it to be worth it. Someone still needs to pay miners to secure the chain. Layers are only as secure as their blockchain.