Yet another of the confounding factors.
But not much comfort to the many small businesses throughout that two-county area put out of business by WM.
The claim in the article is not that WM creates additional traffic allowing niche businesses to thrive, which is often true, but that the WM store itself creates 300 new (presumably net) jobs.
Someone has probably done a national analysis of whether WM has been good or bad for the economy as a whole, and its probably good. Mostly because the lower prices give people savings they can spend somewhere else, in the process creating new businesses and industries.
But I also suspect total retail jobs are fewer in number than they would have been without WM and its innovations, which other retailers have been forced to imitate.
WM is more efficient, which is to say productive, which is to say it gets more done with less. Part of the “less” is number of jobs for a given volume of retail sales.
I guess you are stuck on the idea that there are only a fixed amount of jobs in the world.