RBS Banker Panic

I may have made a logical error here, but...

You know this thing about bank chiefs saying that if they cut bonuses, the supposed best-earning bankers would resign in protest and go elsewhere...

Doesn't that pre-suppose that there are jobs available elsewhere, offering comparable remuneration, without the risk of the bonuses being slashed?

This sort of people aren't known for their philanthropy - that's kind of the point here - so, if these bolt-hole jobs with other companies exist... why are they staying where they are, risking their earnings?

I mean, obviously, they have to get paid their bonuses, but then, if there were good prospects elsewhere, green grass, blue skies and money trees aplenty, wouldn't they immediately flee after getting this round of bonuses anyway?

I don't understand this sphere of life too well, but this bit in particular seems to be a crock.