In many lines of business, retailer profit margins are so thin that it doesn't really matter. But let's suppose it does.
Growing up, we had some family friends who were local business owners, albeit in the service industry.
The first place money will go is the local housing market. As a renter, this is incredibly destructive. If shopping at national chains reduces what my competitors can bid, all the more reason to do it.
The next place it'll go is luxury SUVs. As a (sometimes motor)cyclist, it might help me to get more drivers into Volvos with their safety sensors, though I do prefer to share the road with smaller vehicles. Neutral on this one.
Then it'll go to international travel. None of that money is local.
Then it'll go to investment accounts at national brokerages into multinational stocks on New York-based exchanges.
As far as I know, there is no forum where the local computer parts store proprietor and grocer invest in each other. Maybe some local philanthropy - they might be at Rotary together - but most of the philanthropy around me was driven by the handful of national companies headquartered locally.