"the last affordable sedan in its U.S. model lineup"
AFFORDABLE sedan. So potential Malibu owners will likely move to one of the Crossover SUVs. Camaro base price is $32,495. The Equinox is only about $1,500 more than a Malibu. Trailblazer is actually $2,000 LESS. Trax is $5K less.
The Crossover SUV has been replacing sedans as the vehicle of choice for years now.
Looking at the 2024 Chevrolet lineup:
https://media.chevrolet.com/media/us/en/chevrolet/archive/2024.html
Camaro - "Pony Car", "Sports Car"
https://en.m.wikipedia.org/wiki/Pony_car
Corvette - Sports Car
Malibu - Sedan - Base price $25,100
Colorado - Truck
Silverado - Truck
(Also EV version)
Blazer - SUV/Crossover - $35,400
(Also EV version)
Equinox - SUV/Crossover - $26,600
(Also EV version)
Trailblazer - SUV/Crossover - $23,100
Traverse - SUV/Crossover - $37,600
Trax - SUV/Crossover - $20,400