That stable token is SBD. It sucks at what it does, but Steem did try. Is it possible to make SBD stable by using STEEM as collateral to create it the way MakerDAO does? Possibly, but you have to understand that even though ETH is not stable, its way more stable than STEEM is.

Asset valuations matter, because if ETH went up and down in price a lot, you would have many CDPs (collateriazed debt positions) get dropped. So, the way this would work is that you would have to mint more STEEM as people ditched their debt and you could have hyperinflation.

Part of why it works with Ethereum is that it is the second biggest blockchain in value and status. As far as cryptoassets go, ETH is stable, and it is also essential to the functionality of dapps built on Ethereum. Ergo, it has an underlying value, while STEEM's only current purpose really is to beget more STEEM. Slap a MakerDAO system on it, especially with its current inflation rate, and you'll probably only create a hyperinflating currency that loses momentum faster than the Roseanne show without Roseanne.