You don't think GM has rested rested on their laurels? Have you driven a Tahoe or Escalade? They aren't that great. The 5.3 V8 is not a good engine. Oil consumption and AFM issues are abundant. They do decent at hauling and towing but the ride is jittery. They have always been small in the back due to lack of IRS.
I think their sales are more to do with Ford completely ignoring the Expedition and Navigator for more than a decade and the lack of true competition in this segment. Sure, they have given them mild refreshes (mostly based on what they were doing with the Silverado) and updates that included keeping powertrain fresh(er) but they weren't doing anything ground breaking at all. Ford had nothing to compete with the 6.2 V8 until the ecoboost refresh a couple years ago. In my opinion, they are really the only two options in the segment. The Sequoia was just okay when it came out but it too has been neglected and really only serves any purpose other than to fill a slot for the folks that only look at Toyota (much like their pickup truck). You can pretty much say the same thing for the Nissan. Both aren't as big either. The Durango isn't a competitor either and we all know that.
From the folks I know at GM, the Expedition and Navigator were better than they expected. There are rumors that they were going to to keep the live axle but decided once seeing the Expedition decided to do IRS. This allegedly has delayed the launch date. This is a rumor so I don't know if it is true. We'll see how GM does with their NG models. It is going to be hard for them to leapfrog Ford but I do see them coming close. You got to love competition!!!! The lack thereof is why I think GM has dominated this segment.
This works both ways since Ford has had their own share of problems.....but I get your point. Totally agree with you that Ford allowed that to happen and mentioned that in my initial post. Ford and anyone would gladly switch positions and own the volume, repeat customers, parts and service revenue, etc. any day over Ford or whoever. No doubt the rear seating sucks but it has not hurt them owning this market.
Is their product great-no, but it is pretty damn good. I've rented a bunch of Tahoe's and Yukons-their interiors are pretty damn good, styling is great and I love the cylinder deactivation any day over the auto/start/stop. I rented a Yukon two weeks ago and had to go to their menu to even notice that the vehicle was running on 4 cylinders.
Glad to see Ford and Lincoln swing for the fences on this and come up big-it is about time. Now they need to do that across the board with all of their upcoming products...