I don't think Ford cares if they lose 0.00001% of sales because they lack a manual trans option... I'm with ya, I wish they offered it, but we are just in a tiny minority.
I don't believe ANY domestic car maker offers a manual in a truck right now. AFAIK, GM discontinued the manual in the Colorado/Canyon for 2019 MY and Ram no longer offers it in their full size trucks.
I guess I am OK with an auto as long as 1) it is built to last 200k or more and does so for the vast majority of owners, and 2) the shifter does not take up a lot of interior room. Column shifters are fine, huge consoles that take up 1/3 of the front seat make me feel claustrophobic.
I would bet the current real demand for manual transmissions is somewhere around 10-15%. Take rates are much less than that because dealers either choose not to stock them, or the automaker actually restricts their production numbers for whatever reason, so people just say f-it and buy the auto because that is what they can buy now. There are also those people who have been fed bogus lines like "no one makes them because no one wants them anymore", and then never even bother to look for one, when deep down they really do infact want a manual.
Toyota apparently restricts the manual-trans Tacoma to 5% of production. These trucks never last more than a few days on dealer lots according to several I've spoke to (which also means they usually won't negotiate much, if at all on them). On the used market, people often pay close to original sticker prices for 2-4 year old ones just because they have a manual trans. In Europe, the automatic trans is actually the minority.
My guess is the auto industry is now purposely trying to eliminate manual transmissions from the market because (at least here in this country) they've realized an increasing percentage of people, not having been brought up with them, simply don't know how to drive them. This means as the generations go on, the demand for manuals will indeed continue to wane even faster, which is unfortunate. Certainly they have an incentive to do this because it means only one transmission option would be needed for production of the vehicle.
The rangers tow rating would be cut in half for a manual. I dont think they cared about the manual trans weirdos and cared more about putting a massive tow rating on it. They sell to the majority and unfortunately the manual trans weirdos are not the majority by a long shot. If you noticed ford has really streamlined their powertrain options across the whole fleet. It's mostly ecoboost/10 speed auto. Offering a 6 speed in the ranger to sell a few more trucks wouldn't be worth the time no matter how much 3 people complain about it.
Not necessarily... If the transmission is matched well to the engine's output, there's no reason it can't tow as much as would be safe for the truck's braking system.
Back in the day Ford derated the manuals likely because the chinsy transmissions of the time (TK4, TK5, FM145/146, etc.) sincerely couldn't handle it. It's unfortunate Ford didn't revise the ratings for M5OD-equipped trucks, because there's nothing I see from a mechanical standpoint preventing them from handling the same weight as the A4LD trucks. Toyota rates their MT trucks with the same tow capacity as their AT trucks, so it's not, say, because of too many idiots who can't use a clutch properly.
As you already said earlier, Ford puts a manual trans behind the 2.3L EB in the Mustang (meaning they already have the trans and ECU calibrations for it). Seems they could've easily adapted that trans to fit a t-case (also w/slightly different ratios if needed) and used it in the Ranger. They probably didn't do it simply to keep downward pressure on future demand for them.