Instead of trying to say "these rules apply to only this tag and always when this tag is included", that entire set of topicality was taken to a different site. Consider trying to ask the question "what is the best C complier given XYZ requirements" on SO. Its tagged with "C", "recommendations" and "compiler". Well... that would mean that it shows up in the C feed - and those people don't think its a good question, so they close it. And then the recommendation followers say "but its tagged with recommendation - that means it should be open and its ok if it gets 100 answers." Two different policies on the site. So branch the community - ask the questions about recommendations where a different policy for what makes a good question and answer on a different site.
CodeGolf was that way. https://stackoverflow.com/questions/tagged/code-golf - but two things happened. First, it got lost in the noise of all of the other questions on the site. Secondly, people who wanted to have fun questions with many answers that constantly get bumped to the top of activity were getting their questions closed and down voted because of that fun. So the community branched to a new stack exchange site https://codegolf.stackexchange.com where they have flourished even more than they were when it was a tag within stack overflow.
That Software Recommendations doesn't have the activity and isn't flourishing the same way suggests that first off people aren't interested in moderating or curating the site in a way that attracts more than drive by questions. With a Q&A site it is the Answers that drive if it flourishes or not. The quality of the answers draw other people who want to provide at least as good content. Also, the format for Q&A doesn't work as well for recommendations. Why does it have to be on Stack Overflow or another exchange site? Why not go over to https://www.slant.co where the entire focus of the site is the "what is the best XYZ" - https://www.slant.co/topics/4265/~open-source-c-c-compilers https://www.slant.co/topics/1376/~resources-to-learn-about-c... or https://www.slant.co/improve/topics/7940/~which-open-source-... for example. Different format focused on that question doing it better than Stack Overflow ever could (but that's also because it doesn't try to do a more general Q&A format).