While I understand your argument, I dispute that copy-left makes things inherently less appealing as open source, or that you can make any objective claim that liberal licenses ultimately result in broader utility. 1. I personally find copy-left inherently more appealing (as something to potentially contribute to) purely because of my ideological leanings. 2. While the first order calculation of use for liberally licensed software seems clearly in favor of them, it's impossible to ever know what benefits the copy-left restrictions would bring one or more orders removed from the original distribution.