We must remember that companies do earn a crust from us coming to work, we are not just a perpetual drain on financial reserves for no reason.
Every other industry I can think of sets their prices according to their costs and expected reasonable profit. It's called a business model. Training costs are part of that model and are taken into account when setting prices. It is well understood, in the airlines I've been involved with, that a 10% per annum attrition rate is the norm. This is based on retirement, medical and 'moving on'. It is budgeted for in the training/recruitment model. What has happened is that the rapid vast expansion has been based on low prices. It could be discussed that it has been a price driven expansion not a demand driven one. It has become so cheap it is too good to miss. Rather than drive to the local beach let's go to a foreign one; or foreign mountains. To maintain this profit driven, rather than service driven industry, costs have had to be driven to the lowest. Think Tescos/Liddle/Aldi of the airline world. The start point is training costs. The next point is keep everything as basic as legally necessary and make it as safe as possible. (I still say this model would not have been possible in B727/737 days. SOP trained monkeys wouldn't have cut it.) Now the public are so used to cheap everything, they'd even load their own bags if they had to. I remember a time in 80's where charter pax picked up a lunch bag as they boarded the a/c instead of catered food. It was too expensive to serve hot on board. The genie/toothpaste can not be put back in the bottle. I still fly national carriers, often at cheaper prices than the local LoCo. The market has caused a response and the nationals have responded. They still make profits; might be cross-subsidised, I don't care. I get national carrier service (sandwich only) at LoCo prices. Salaries have not been slashed across the more realistic flexibly minded nationals. They are expanding and profiting. LoCo is not the only way to go. And I don't think the nationals have gone down the P2F route, yet. So there is another way. Let's not just assume there is only one working model. Tesco is no longer the only market leader.