DFS, discussion is always good, as I take no offense from message board commentary.
Regarding your 7-10% rumor—I doubt that Raptor sales have/will ever be more than a small volume niche seller compared to U.S. or global F-150 sales. We are talking units of F-150 sales volume. High prices will always keep the sales volume of the Raptor (and niche cars/trucks by all manufacturers) very low as a % of units.
The luxury perception/off road image, and of course profit margins of course are high—but the profit margins are also high on F-150 Limited, King Ranch, and the high end trucks by most OEMs. I’d guess that the traditional loaded F-150s outsell the Raptor by a good margin and always will—thus making the Raptor a niche/halo in an overall category.
Top of mind, a handful of advantages of IRS include: improved ride quality/comfort, handling both on/off pavement, higher speeds off-road (to match the “desert runner” marketing). IRS would also differentiate the Raptor.
There are significant challenges with independent rear as well including weight, complexity, and likely engineering/packaging in a manner that is functional—good number of downsides. That is the fun of pondering I suppose.
(Edited: Also a rear lift is more complex on an IRS vs solid axle—but that’s not a concern).
Ultimately, it will be interesting to see how the pickup truck market evolves over the next decade or so!
