The reluctance to declare a fuel emergency or call a MAYDAY isn't simply the issue of paperwork..
Declaring a fuel emergency will result in an enquiry that under circumstances such as these is likely to reflect badly on the captain's decision making and result in a blemish on the pilot's record that will affect his future employment prospects with a major airline, or even threaten his current employment status.
This threat combined with what psychiatrists term 'cognitive dissonance', (the unwillingness to accept what's happening) results in an extremely strong reluctance to act rationally to a set of circumstances.
Many pilots reading of these events would be surprised at how susceptible they themselves might be to these pressures even had they'd not felt themselves guilty of any rash or imprudent actions during the flight planning stage.