DigixDAO works on tokenized gold. If there is demand, we will see every possible good as a token. It shouldn't be that difficult to make an virtual product like an ETF into a token on a blockchain.

There are financial incentives to create and destroy DAI. A user of DAI doesn't need to collateralize, he just buys DAI.

DAI demand will grow, if the use cases grow. It is also a good safe heaven for crypto traders.