Re: Is this normal?
Airlines have a brutal load of IT-based legal requirements beyond the normal corporate, from maintenance to aircraft movement, to staff rostering. Each of these has bespoke or small supplier (often the commercial arms of other airlines) software on the latest next-big-thing mapping a history of IT back to the 1950s. Delta has previously been in trouble for running its loadsheet generation in a cupboard on the fifteenth floor of an office building.
Why bespoke? Well, look at BA's SAP implementation to replace its parts system and the damage that caused. Off-the-shelf generic solutions either don't exist or are monstrous to implement.
Why so slow to upgrade? Each of the systems is connected in fragile ways to the operation of the airline. Replacements for ancient windows servers have to work in pretty much exactly the same way and that's really quite expensive. Airlines go from broke to rich following the business cycle and back to broke again. IT re-engineering projects have very low priority and the landscape is full of sharky outsourcers long on promises, short on everything else. Meanwhile investment goes into NDC capabilities, offer-order, personalised offers, a vision that offers little to the consumer and even less to the airlines.
Airlines are not Amazon Retailing, they're not Google search. Anyone selling you that is peddling snake-oil.