The lines are blurring between low cost and legacy. As low cost improves and legacy cuts service to compete, the gap narrows. There used to be defining line between them of free meals/drinks/baggage, but that is being crossed as BA cuts catering on short haul, Aer Lingus charges for baggage and many even charge for seat selection.
Some low costs even offer a premium cabin which, whilst not as good as legacy business class, is an attractive option compared to the paying 4x the regular fare to sit upfront on a full service airline.
A whole generation has grown up with the internet and is comfortable with the new pricing methods, booking online, and knows how to compare prices using search engines. As the older, pre internet generation dies off, legacy airlines may be in more difficulty if they don't change with the times, as these people are their traditional customers, wealthier and less inclined to shop around.