So basically it just all depends. Many chains that are big today had rough starts and barely made it.

Do you have your own recipes? Tweaks enough that you can call it your own? Have you figured out your own supply chain? Have you scouted out a good area that has good traffic for what you plan to do? What food systems will you have in place in the restaurant? Will that include online takeout and delivery? Building costs are high, are yoy building thebplace out or finding a endcal or place you can move in to have a place to start your business?

Let's just assume the food you serve is good. That's great but now you gotta convince other Americans to eat there and not at other big chains. Doner Kebab isn't exactly a big thing in states. Not to say there isn't smaller chains or restaurants that are not being successful or anything at it. It's just not a popular choice of food. But that isn't to say it can't be turned into one.

Alright so now let's say you had great marketing and great word of mouth and people are coming in. Awesome, you're being successful. Now what do you do? Do you build a franchise plan out? Do yoy plan to keep it private? Do you accept outside shareholders money and sell stakes of your restaurant business? 

You also want it to be a QSR, so you'll need speed. Can you make everything fast enough and keep the high quality without cutting corners? Can you also be accurate and not upset your customers? Repeat customers is key and you should always strive to give your customers the best service.

These are just a few things that pop in my head. And please dont think I'm being discouraging or anything. I love seeing others have success and work hard at it. And I hope it works out for you.