We buy our ticket from the airline but they don't get service guarantees from the airport so all the risk is passed onto their customers who can miss their flight and be held responsible for it, despite it being the airports fault.

The incentives for the airport are to be as cheap as possible, which they do by not having enough staff manning bagging/security et el for the peaks. Airports are a natural monopoly within an area so there isn't competition to loose out to, there is no where else for the planes and travellers to go and cities wont be putting down space for multiple airports to compete.

Because of the monopoly aspect it requires legal requirements for service guarantees to be laid out on the airports to fix this, without which the situation wont change and the risk will continue to lay with the customer for airport failures and they have little choice but to turn up early to mitigate the risk of the airport not having enough capacity. Its a system where all the companies are acting in their own best interest.