The BRAL routes were not supported particularly well by BA who controlled the ticket sales and unfortunately, the available seat mile cost per kg of fuel for a regional jet with a 60% load factor is not good when compared to a full A320/B737. If the airline wanted to offer the high frequency rotations demanded by business travellers like 3 departures per destination per day, the fare had to be high enough to offset the low load factor and it became a bit of a Catch 22.
Low Cost Airlines avoid this by filling the aircraft, but often don't offer the high frequency and are like any budget business in that they pile them high and sell them cheap.