They did for the diesel until last year. IMO very probable limiting it only to the diesel and I think it was a higher trim only option killed it. I am sure very doctor and lawyer that plunks down $50k+ for a loaded diesel ZR2/Bison wants a manual too for their luxury offroader.
I have built many a manual V6 Gladiator on Jeep's website.
I keep forgetting about the Gladiator (I guess 'cause it's still so new... the Ranger, at least in name anyway, has been around for decades.). You've only one body style option with the Gladiator though (crew-cab w/6' (I think) bed), which makes for a very long cumbersome truck, impractical for even moderate offroad trips (which is what I'd use the pickup for... my BII (or if the upcoming Bronco is decent) would be for the much more technical stuff).
Yeah I've no interest in a "luxury offroader" either (and infact Toyota doesn't offer the manual trans in their "Limited" trim). My desire was a basic manual pickup with some amenities (cloth seats, V6 engine, 4WD, A/C, CC, CD stereo with HD & RDS reception, and a (manual) sliding rear window).
Off-road manual trans only has one advantage, downhill slowly
Not true, a manual also allows greater finesse maneuvering through large rocks... But there is a caveat, you MUST be geared for it. Excepting maybe for the Jeep Rubicon, no manual 4x4 comes with deep enough gearing allowing for this from the factory, and so is why aftermarket crawl boxes and t-case doublers are common in manual rigs used in rocks (perhaps the 7-speed manual in the upcoming Bronco will allow it, if it has a decently-low 1st).
Automatic has the advantage of no lost momentum shifting gears going uphill
No argument there. However I think that is less of an issue than in, say, in a mud bog. The loss of momentum from trying to shift a manual in a mud drag is likely to be the death of any chance at a win against an automatic. I've no desire to run in deep mud though, so this one isn't an issue for me.
It takes more skill to use a manual well, but its not really a needed skill any more, lol
True. But I find it a lot more fun too. It provides for a much better connection between man and machine.
Manual also has the edge in reliability, which is a big deal 50miles out in the bush
Has an edge in longevity too (possibly another reason why the automakers are turning away from manuals, they tend to stay on the roads longer, meaning fewer future sales). They tend not to overheat offroad too.