Well the airlines do. It is their airline, and they can apply whichever business model they see fit. The more they erode the robustness of the fare structure in that model, the more they erode the number of passengers who will pay that fare (why would they when leniency is shown or sub-rules apply which add flexibility?).

Be careful what you wish for. The airlines need to make it pay somehow. Without people paying much more for last minute fares, or for flexibility, we will all have to pay more for our cheaper more restrictive tickets.

You have suffered a big loss. It is the most human thing in the world to try to seek blame or hold a grievance, rather than accept what happened, and take the hit, and bear the responsibility, with all the difficult feelings that come with that.