John B wrote:

Instead, it achieves the opposite. Which makes me think that it's not
complex discrimination, but just a way of filling a few empty seats
very very cheaply to the company (and to the passengers, of course).

That's exactly what price discrimination does, it allows them to fill
empty seats with cheaper tickets without abstracting away revenue they
already have. It's designed specifically to keep people like the OP from
doing what he wants to do.
--
Michael Hoffman