I understand the theory, but practice doesn't work like that. Lost customers and brand are lost. And new competitors stick around.
It's why they push it harder when theres a convenient excuse to raise prices. Less reputational or brand harm if you get to blame Middle East, OPEC, hurricanes, inflation, etc.
And for a lot of the big ones, they can always drop prices back and crush competitors before going back up.
Which is fine because Big macs aren't a human right.
Churn is acceptable, if not desirable.
Customers have several burger options beyond McDonald's. That's good old capitalism.