Now granted, the Flex exists and it's never sold more than 40k units per year, and the Expedition sells less than 80k units since 2008. However, the Flex has never been considered a success (I dunno why they even keep building them) and the Expedition is in many ways a modded F150, so it's easier to build / stock parts for.
Maybe, a US Ford Everest could be a cheap solution, but a US Ford Everest wouldn't really be competition for a JK. Also, Ford's current NA market plan is, to a degree, trying to cut down on models so that it's easier/cheaper to stock parts and build cars. That was part of their reason for taking away the Ranger in the first place.
Some good points made.
I'll add some and say that the Expedition's R&D is fully recouped by now. The current gen came out in 06 as an 07 model, which means R&D occurred in the early 2000's when the SUV boom was still hot. It's now very long in the tooth and the much needed 2015 refresh helped somewhat.
Part of what makes Jeep successful is a combination of heritage, fanbase, and absolutely HUGE aftermarket. All three seems to depend on eachother, and together make the Jeep community what it is. Take the Explorer for instance, it sold in very high numbers in its heyday, but never created an aftermarket remotely the size of Jeep.
Same for the Xterra. A decent IFS off roader, some aftermarket, but not close to Jeep despite some loyal fans. 4runner & FJ, same thing, decent aftermarket, better than Nissan's, but pales in comparison to Jeep. And now, a decade later, the 4runner is the only one left.
Hard to imagine that somehow, Ford can go against all odds, and come out with a worthy competitor to Jeep, capturing all the charisma of the Wrangler. Never mind capturing 70% of Jeep's market...