From my recent First Class journeys in the South East, I have found
that demand for it is practically non-existent on suburban routes
outside of peak hours - this is particularly my experience on the FCC
Bedford-East Croydon service.

However, I have found that these operators now have an off-peak 'First
Cheap Day Return'. FCC have this, as does FGW. Why do very few
people take up these offers, which seem to be good value for money?
Is there a general assumption that First Class is far too expensive?