"if there is a company in the cryptocurrency space that can pull this off, is probably Coinbase"

I agree. Coinbase is probably ideal. They are half crypto enthusiast/half bankster, the perfect hybrid.

I very much want ETFs to get the go-ahead, and Coinbase might manage it. Like you say, it will lock up a bunch of coins, and raise their value by restricting supply, but more importantly, it will get investment publications writing analyses of all the coins, and that will be to Steem's huge benefit, because it is the only one being used, every day, by ordinary people. :)