There’s a reason why premium fast food has spread so much.
By the time you’ve paid your business rent, your staff and your own rent, you can’t keep prices cheap and still make money.
And at a price point that covers your expenses, people won’t buy your “cheap and simple” food.
So you make your food “premium” cause a hipster burger doesn’t take more time or skill to prepare than a normal one, the cost of better ingredients doesn’t make a difference compared to your other expenses, and all you need for people to be satisfied with the experience is a couple thousand extra initially for interior design and marketing.