Comment by kmoser

I think it's a combination of several factors: first, most banking and airline systems were developed back in the 1960s, and it was simply more convenient to shoehorn everybody into the first-middle-last format, especially when the majority of their customers did fit that model.

Second, this was before the government (and businesses) were so picky about everything matching perfectly, and you could get away with mismatches more frequently because you had more human eyes looking at things. Those humans would easily realize that when the customer they've known for years as "Jane Smith" shows up with a birth certificate reading "Jayne Smith," it's the same person.