Well, I'm sorry. I respectfully disagree. I've been a businessperson long enough to understand that good concepts can, will, and should be duplicated.
I agree, however, to the point that sometimes atmosphere is sometimes the only thing that comes across in chain operations.

Another...more common....example of what I was thinking with "late great" was Chi-Chi's. Never really authentic....but a fun place where you could get pretty good food at reasonable prices. After a few years this had run its course and become universally bad food in dirty, unappealing, if not surly surroundings. Come to think of it....same goes for El Torito, which has limped along for more than half a century.