GM has made shyt products for a long-time. There is a reason why they were going bankrupt. Their cars were of low quality, and they were total unreliable.
My parents used to only buy GM until the engine fell out their Blazer while driving on the highway. they then switched to Honda and never came back.
Who the hell wants to drive a Caddy? Or an SUV? Or a Chevy period? Nobody. California is probably the most important market, and I don't see anyone driving GM or Ford for the matter. I do see plenty of BMWs, C-classes , teslas, Scion FRSs, Cammry's, Accords', Nissan Z's, G37's , Mini coopers and Audis. GM really has nothing that can compete with those cars.