Following delistings, Monero will need to also decentralize it's price tracking.
How can the monero price can be known in a decentralized way ?
Like aggregating DEX prices in a oracle ? Or fetching directly DEX public peers ?
on the major existing decentralized exchange, Bisq, you already have a publicly observable price feed for XMRBTC. you can calculate XMRUSD based on that and a BTCUSD price feed that you trust.
DEXs that are in the making, namely Serai and Haveno, both plan to have at least one XMR pair with an Ethereum-based dollar-pegged coin. I suppose, although I'm not sure, that at least in the case of Serai the trades on that pair will have publicly observable prices.
Haveno will also have non-blockchain, actual fiat (cash, wire, payment apps) pairs with XMR.
you can take sources like this and calculate an average or a median. current price aggregators, like coin listing sites, will probably do the same, so it's likely that even in a DEX-only future you'll get your prices from the same sources as today.
This is good. Hopefully the other decentralized services that spring up will provide data so something can be set to ingest all the data aggregate it as tusker suggested.
This is a great question, I hope we will have some reliable way of aggregating all the DEX sources, sounds like a good opportunity for some talented coders.