Wikipedia works a lot better when entries are kept as close to a single unitary concept, broken up into distinct entries as they grow. This not only ensures maximal specific interlinking but it also is crucial to using the process of accumulative edits to ensure improvement and refinement of the content. The longer an entry gets and the broader the range of concepts it covers, the less likely there is to be a consensus on what is proper form for the entry.
Moreover, it simply gives you a more asthetically pleasing and consistent experience.
See the difference between an "agglomerationist" version of "sport" and my "atomized" version (which also involved the creation of sportsmanship, history of sport, professional sports, asthetic appeal of sport, nationalism and sport, and regulation of sport).
Another example: From content from the still-too-long homosexuality entry, I created or reworked societal attitudes towards homosexuality, sodomy law, sodomy laws in the United States, persecution of homosexuals, reparative therapy, gay disease.
The primary (and essentially only) benefit of agglomeration is that it it makes for a better printed version (if well done, which is unlikely given the wiki editing scheme). But that is not the primary goal of the Wikipedia. The fallacy of using paper encyclopedias as a model, which also leads to deletionism, is pernicious.
It's true that there should be better methods of linking up related entries into a single page if one so desires, but that is ancillary to the primary goal of Wikipedia.