No you don't get it. The monero Blockchain can be verified by the pubkey, which only you should have anyway the transactions in the block don't matter from decentralization point of view, the crypto is solid and the format is probably not malleable. So it works perfectly.

While Zcash is totally dark, which means that it totally relies on the trusted initialization phase. And Dash is totally open with "optional" privacy whic is also very weak.

Monero is both trustless and private, it's the golden mean between decentralization and privacy.