I seem to recall a retrospective where they did examine many of the restaurants he visited in Kitchen Nightmares. All of the ones that closed were due to the owners failing to follow the advice given, too deep in the red financially to climb out, or a rare instance of insight where the operators decided that running a food establishment wasn't for them.
I mean, they were all in bad shape and going to fail without Ramsay's help to begin with, so failing to follow an experienced chef and business operator's instructions on how to fix things is a surefire way to seal the business's fate.