I get it you don't like the rat.
More correctly, I do not like what I get for my money on the Rat these days.
I always used to book Ansett, because it started in a town where I used to live. Then I always used to book QANTAS, because it was Australian.
Same way I drive a Ford because it's the only thing designed and made in Australia (and it's not as awful as the Holden fans would have you believe...)
Other airlines planes are just as old. But nowhere near as dirty and uncomfortable!
Or expensive: SYD <--> SIN on a 388 in August:
Singapore Airlines
: AU$843.52
QANTAS: AU$937.84
It's not competitive not because it can't, but because it won't. It's choosing not to.