17 worlds are advertising in the classsifieds, 6 public worlds are unfilled, 21 worlds are eligible to roll in the next 7 days. Just assuming that some of the 27 worlds are also advertising, we've got at least 30 worlds to fill in the next week or so.
I'd be fine with letting the problem solve itself. But, if you want a healthier game, some permanent action has to be taken.