The parent mentions DEX volume, which tracks on-chain wallet usage, not what is being traded in a CEX.

> Real-world transactions need to be reversible, need escrow, guarantees and a lot of other mechanisms that are by design not available using blockchains based assets

Many blockchain transactions have reversibility, employ escrow, and have very strong cryptographic guarantees.

The only point of your post that is not easily refuted is: blockchain is not decentralized enough. But compared to what? Is Ethereum, open source software with many thousands of nodes and developers spread across the world, more or less centralized than the US dollar?