This article from Nieman Lab is a good summary of why local publishers matter (and WordPress is their main tool).
The article is a summary of a research paper. To sum it up in a sentence: When papers are sold to corporate owners, the number of local articles can fall by 68%.
1. Acquisition leads to a significant, but not disproportional, decrease in the volume of local content produced by local newspapers;
2. Coverage of local places in the periods following acquisition is significantly more concentrated than coverage in the periods prior to acquisition;
3. Articles produced to be shared across regional hubs of newspapers are significantly less local—and discursively more national—than articles unique to a given newspaper.
This is the reason that we feature so many exciting new WordPress-based publishers on this site. Almost all of them are locally owned and operated. WordPress publishers are filling the gap left by old newspapers that are falling under corporate ownership.