The only criteria to merit joining Kollel, according to the Rambam, is being a Jew. IOW, the Rambam clearly states that every Jew is entitled to choose to join Kollel. (Obviously, it goes without saying, he must actually learn [not batul] in Kollel. But the Rambam imposes NO requirement that he be a “better learner” or whatever.)
I do not believe that the word kollel was part of the Rambam’s vernacular. Additionally, the Rambam found it distasteful, maybe even forbidden to make money
from Torah. As far as I understand the term Kollel as used today is about 150 years old, tops. Please provide sources for your statements.