Of course, the only people to sell these too -- for the most part -- would be domainers. Two problems with that:
(1) Those other domainers (if they like .DOMAINS) will already have spent their load on .DOMAINS domains of their own. So they won't want yours.
(2) Domainers are cheap. Remember, the goal is to buy at wholesale prices and sell at retail prices. Domainers are accustomed to paying pennies on the dollar. And, as a seller of .DOMAINS domains, that's your best-case scenario!
The only practical reason for registering .DOMAINS domains is to use them in your own business within the industry. But how many of those can you really use? I mean, if you've got 5-10 .DOMAINS domains and 5-10 domains in .COM that contain "domains" or something similar, are you really going to develop a few dozen sites just for domainers?