"Crypto hasn't decentralized anything, because it is funneled into exchanges and fiat is spent on the ground. "
There are some great decentralized exchanges and I am sure you have heard of BitShares where anyone can create any pairing.
Some other great Dex's are
https://oasis.app/trade/market/WETH/DAI
Check out this article from Yahoo on the volume these Dexs are starting to get
https://finance.yahoo.com/news/ethereum-dex-volumes-grow-200-150855718.html
Even if Dexes could be completely anonymous, which they can't, it is simply the case that you cannot swap for cash fiat without routing through legacy mechanisms. In 100% of cases, getting cash in exchange for crypto involves KYC/AML regulation and surveillance.
An anonymous dex (if one could exist) could issue a card to HODLers that when used to make purchases could debit your crypto HODLings, yet compensate the merchant with fiat. This isn't possible, despite being obvious and having been tried. Without a bank account, you're not getting fiat from your crypto.
Wirex?