Why do people ask relationship advice from people who are in failed relationships or who have had a number of failed relationships?

I’ve seen people who consistantly ask relationship advice from people who don’t seem to be able to maintain a relationship and then wonder why did they have another relationship go bad.
Wouldn’t it make sense to ask the people who seem to know how to handle a long relationship?

Yet people wouldn’t ask their grandmother how to fix their computer (unless she is a tech) or ask an electritian about gardening tips or an electrictian about health matters.
So why do some people ask friends in weak relationships, rather than the friends they have that are in long working relationships?