[Sohcahtoa82]

I'd flip the question the other way around.

Why does becoming a chain automatically disqualify a place as being fancy?

I think people apply a lot of assumptions once the word "chain" has entered the chat. They assume they've entered a race to the bottom on costs to maximize profits, but there are plenty of chains that I would still consider on the fancy side. Fogo de Chao and Ruth's Chris, for example.