I often see this question asked but its not really a fair question. Generally speaking, fans don't have access to the same information and intelligence that clubs and agents do. As always there are exceptions. How many of these fans know the details of other Scots managers', assistant managers', and coaches contracts (if indeed they have one) for example? How many candidates would appear out of the woodwork if our club approached them directly through their agents ? How many current senior players with other clubs might apply?
Now to my own ignorance. I didn't know until recently that some individuals will not apply for vacancies, but will only become interested if they are directly approached. That was news to me.
Then there's England. The same questions apply only moreso. How many of our fans know much about English lower league managers? Without checking up through Wiki, how many of our posters could give you a run down on the managers and their assistants at say Gillingham or Bristol Rovers? How many of our fans know much about coaches at clubs like Birmingham City?
I won't go on to potential overseas candidates.
In general, how many fans have a reasonably good knowledge of potential candidates' characters?
These questions are hard enough for clubs, in the know, to answer never mind posters on this site.
All this said, there is no cast iron guaranteee that if a manager is replaced, his replacement will be any better.
I would pose the question though that if a manager is deemed to failing (who decides that I hear you say) is it better to bring in someone who might fail? All such posters can see is that the manager of their own club is failing or underperforming.