Gotta chime in, please don't beat me up too bad.
Why would I, or any other professional programmer, want to invest weeks or months building a rock solid script that facilitates the people using it to make $1000's per month - just to give said script away for free?
There Are powerful scripts, like osCommerce, that fare quite well in the open source community, and it is because the same people that are participating in the future development of the application and the many hundred add-ons for it also are USERS of the it. They all share in the benefit of the script being open source and free.
I don't think it is viable to attempt the same level of benefit by offering a LinkList script under open source because 99% of the link list owners can't program their way out of "Hello World" - and I don't mean that offensively. There just is no beneficial trade off or incentive to offer such a script this way.
Applications like osCommerce have a VERY ACTIVE following of developers and users that work together daily to address issues, find bugs, develop enhancements, etc. The same will never happen with a quality link list script. There simply just isn't enough of an audience of people capable of contributing to make it feasible.