DAI represents less than 6% of the current stablecoins marketcap. It's just not big enough to be representative of the whole market.

DAI is great in principle and is built on fascinating technology, but the incentives for issuing DAI are not worth the risks. DAI is only created as a means of leverage, you take your collateral, lock it into a contract and receive 1/3rd of the collateral's value back in the form of DAI with the idea being that you can immediately sell that DAI and buy more crypto with it. But because of this, DAI is created precisely when its demand is fairly low and it's destroyed precisely when its demand is fairly high.

When crypto markets are volatile there's more demand to cash out of crypto and into a stable coin, but volatility is also when people take on the least amount of leverage meaning that it's also when there's the least amount of DAI available.

When crypto markets are not volatile, then the utility of a stable coin goes down and yet that's also when people assume the most amount of leverage and hence when the most amount of DAI is available.

The end result is that the incentives for DAI don't really work out all that well.

DAI is small and half of DAI collateral is USDC in any case.