I think If they raise the renewal fees to 50$ they would lose more than 10% of registered names and lose part of market share
If they raise it to 100$ they would lose more than 30%
More than 100$ , they will destroy the extension
So do not worry , they will keep as cheap as possible
And without the new gtlds , the .com would have been much more expensive for renewal and resale
Market competition is better for prices