I don’t subscribe to the ‘cheap seats at the back’ model any more than putting an Ibis inside a Hyatt hotel. They are completely different business models appealing to completely different segments of the market.
um, better parallel would be an Ibis in a Sofitel, Hyatt is a different hotel chain.
Agree completely with the rest of your post and you only have to look at Air Canada/Rouge, Lufthansa/Eurowings, IAG/Level (LH low cost complementing its’ premium airlines BA and Iberia) as a few examples of the QF/JQ model being used to protect revenues.