Old town downtowns - small ones - have a real economic challenge. This example of Hanover, Pennsylvania discusses part of it.
But one thing not mentioned much is the balance between useable economic space, and roads, and parking. Building an economic base in a downtown at this point unfortunately relies on cars. Either it will be stores, drawing shoppers, or employers, drawing employees... or a town needs to find an employer base that brings economy to the town and somehow doesn't draw cars.
But old downtowns have small roads and usually have little parking area beyond what is available on the road.
When we moved to Harrisburg 15 years ago, Harrisburg was one of the saddest downtowns I'd ever hung out in. The Spot, which I know is revered in this area, was the primary culinary highlight.
The city focused on developing business and parking, and the city has flourished the past 5-10 years. Now, Harrisburg's focus on restaurants and bars can't be for everyone - Harrisburg does have a major advantage with all the lobbyists, legislators, and government employees looking for lunch and something to do after work - but the parking was very important. Nobody wants to walk in slush for 5 blocks to get to a restaurant on Saturday night. Now, in Harrisburg, you don't have to.
Pennsylvania is full of these small downtowns. They do need to have a plan to avoid becoming dead shells creating greater cost to a small city or borough. Good luck to Hanover.