I think it makes sense as a local minimal during a process of iterative compromise. They arrived at 'if it ain't broke don't fix it' and shall stay there until changing conditions break this stability.
What you are saying, that Britain and other countries keep monarchies around because "if it ain't broke..." I understand, though I still think it's pretty weird.
The comment I was responding to, which makes no sense, made the non sequitur that "Americans seem to think that constitutional monarchs are like the president of the US" because he only read the first half of my sentence.
IIRC the last time the Brits tried to get rid of their monarch it didn't end well and the people decided the monarchy was better than that chaos.
QE II wasn't a bad monarch, and that was probably a big factor in the UK keeping its monarchy during the 20th century where democracy was the big trend.
The comment I was responding to, which makes no sense, made the non sequitur that "Americans seem to think that constitutional monarchs are like the president of the US" because he only read the first half of my sentence.