I always wonder why some franchises exist. Why would I want to pay Subway money? It's just a shop selling sandwiches, and its appeal is that it has a variety of toppings. I can go to Taste, buy the bread and a bunch of toppings, open a shop and sell the sandwiches. Why on earth would I have to pay someone to put the name "Subway" on the top of my shop? People don't come to my shop because of the name, they come because of the choice of toppings. Same for all the pizza shops.
Besides, many of these franchises are US based. For example Domino pizza. You pay to use the name Domino, but in HK nobody even ever heard of this name, so you can as well open your own shop and call "Diamond pizza", which is more catchy than Domino, and you save the money you pay them. And don't tell me you pay for a superior product. All these American franchises are basically disgusting (starting with Pizza Hut).
The only shops that sell something "unique" (almost) are MCDonald and KFC. They are difficult to copy because so very yukky.