Dear Terrier,
As Hotel Mode just said.....BA have a completely different cost base then most of the smaller or no frills airlines.... BA needs business pax which offer High revenue compared to the leisure traveller or the cost conscious business man which many of the more regional or low frills airlines compete for. BA tried to best suit the regional airlines by establishing the City Flyer franchise yet that too backfired so it obviously just is not somewhere BA can compete effectivly.
Easy jet can fly a less then full load and still make some money as they have a lower cost per mile then ba.
Unfortunatly many national carriers seem more like serving everywhere else other than its own country. I can remember when I could fly from the remotest part of the west of Ireland all the way to LA with Aer Lingus...but look now....no shamrocks anywhere but the main airports!!!