Well, not just foreign, but we seem to always have to go with Premier League and now Championship experience when there are potentially some very good managers abroad, or even in the lower leagues (though I can't think of an example of someone putting their name in lights right now), that we ignore for some arbitrary reason. Good managers are good managers, and we should be trying to find them.
Bielsa and Mancini don't have jobs currently, a bit fanciful yes, but why not throw money at them to see if they'd come? Mancini almost joined Notts County when Sven was there, so why not join a team that would be 2 divisions higher? Instead of restricting ourselves to the same old tired English managers, why not look for someone with a good reputation abroad?