Yes definitely. The degree varies by establishment. Most of the shops downtown -- the art stores, rock shop, gift and clothing shops in particular -- are utterly dependent on tourism. Locals don't buy local art and crafts, and they don't buy leather jackets and hats tastefully embossed with the town's name.
The town's grocer is pretty dependent on vacationers. Locals do more of the 45 minute drive to Walmart once a week.
The restaurants in town get more local business, but I'm aware from comments and reviews that our guests eat out a lot. Even with a full kitchen, it's common for people to eat out more on vacation than they would normally at home, especially when the restaurants are seen to be part of a town's charm and reputation. Which is why I put out the menus on a side table in my home's entryway, just like the hotels do in their lobbies.
When we bring family there, we eat out a lot. We walk downtown to get ice cream in the little candy store. We never do that at home in Denver. I don't take the kids to ice cream at home. That's what vacations are for! I say, "You are naughty, awful, disappointing children, but if you be good from now on maybe we'll go on vacation again and get ice cream". I know I'm not the only one.