Considering the amounts of flights, I'd say that being able to book your travels without calling elimited the costs of needing phone operators. And allows me, as a user, to also easily book outside of office hours.
I agree that there's a lot of useless tech around. Especially in this startup world where it seems to be all "Uber but for x".
You also haven't answered my question. What would've been a non-useless tech that should've been developed on in the meanwhile?
And just because some commercial companie (travel agencies) spent their profits streaminglining their booking process doesn't mean it's all been useless these last 30 years.
Why not? Technology has opportunity costs. Usuless "easier" technology makes us slaves to it and to increased infrastructure.
Opportunity costs, diminishing results -- all those are good questions to ask.