GM, Ford make great trucks. No one is denying that. The demand decreased when people stopped being able to afford the gas on those trucks.
On the other hand, have you ever owned a small American car? Well I've owned several. I now own a Honda Civic 2000 with 60 000 Miles. Although it is obviously a small sample, I've ever experienced less issues with the car I drive now in comparison with the American small cars I used to drive.
That's the problem. The big 3 got dominated in the small car market and that's what the majority of middle income Americans/Canadiens began to purchase.
When the big 3 can make a car as durable as the Honda Civic from the early 2000's or Toyota, that is when they will regain their market share.