What I've gathered left and right wrt the airline industry is that it was one of the earliest industries that went digital, and / but they have a lot of legacy going on.
I mean in this particular case, they could have Abbott create an account on their website first, but then, someone else booked the ticket for him so that makes things more complicated (because they don't have an e-mail address), and then there's tickets being booked all over the world, and then loads of people don't have computers or e-mail.
The amount of pain still caused by things like somebody back in the sixties deciding that two characters is plenty to encode every single airline ever is still felt to this day. Witness the majesty of the "controlled duplicate": https://en.wikipedia.org/wiki/Airline_codes
I mean in this particular case, they could have Abbott create an account on their website first, but then, someone else booked the ticket for him so that makes things more complicated (because they don't have an e-mail address), and then there's tickets being booked all over the world, and then loads of people don't have computers or e-mail.
It escalates quickly.