I wonder if that will really prove the case with Little Red, Alex.
When you book ahead they both offer competitive prices. For example a trip to Edinburgh between 9th and 11th September has minimum price of £108 economy whereas you can get less than £100 on East Coast for first class and as low as £34 in economy.
The fact that Little Red are regularly flying round with less than 30 pax suggests that model is fatally flawed. Personally I would take the train any day.