There is a fundamental difference between the two, not just semantics.
A restaurateur that has more than one property is quite different than a large chain restaurant. There are capital and management limitations to how large a restaurateur can grow before it become a chain establishment. I am not sure where that line exists when an establishment becomes a chain. Is it when they reach a certain number of locations, become publicly traded or ??????? Almost all of the best known chains started as single restaurants and morphed into chains somewhere along their history. Still, I do not think you can call a chef with several restaurants a chain.
When discussing chain restaurants, there are really two defining attributes to examine, scale and price points. You can almost chart this, if one was so inclined.
As a chain increased in scale, quality almost inevitably decreases. I am not talking a direct correlation, but close. National or global chain with hundreds or thousands of locations will focus on uniformity and profitability, not product quality. This is not all bad as there is some comfort knowing that the McDonald's french fries will taste the same in Wyoming as they will in Chicago. The down side is the McRib will taste the same as well (one of the worst things I every tasted). Many regional chains still owned by the founder often refuse to expand beyond their region for fear of diluting the quality of the product.
As one moves up in prices, quality will usually rise accordingly. It is inappropriate to compare Morton's of Chicago with Steak and Ale. To be fair, comparisons should be grouped together, mid-priced italian restaurants, high-end steak houses, fast food chains, etc. You can also group them by menu price points, say best meal for two under โ.
When I refered to suburban chain restaurants, I meant, but did not clearly state, I was talking about mid-priced chains.