They can't even afford to have mass production for 15/16 inch laptops, I don't believe such a niche target is within their realm of possibility.
There is no modern laptop like it where you can keep a chassis and update the thing piecemeal, easily buy parts for it, designed from scratch to be easily repairable and comes by default with a sensible system for choosing your own ports without external dongles hanging from delicate ports.
The market for a three screen laptop is much, much smaller than that and it would probably work better as a third-party accessory to the base Framework. Of course, it wouldn't make much sense because their only chassis has a tiny screen, but if you believe a three laptop production line is economically viable, surely you also can see how a MBP-like 16-inch screen production line is even more viable.
As I said, barely differentiable. Baring that, its as standard as a plastic laptop comes.
I'd personally be more interested in a portable than another laptop. Most laptop's I've owned have not needed repair for their lifetimes, and very seldom have I ever even thought about needing to upgrade my laptops "piecemeal" rather than just upgrading the whole thing together.
If I wanted a 16" MBP I'd buy a 16" MBP. Plus it can run MacOS.
What nobody makes is a portable workstation rather than a laptop. Laptops are great if you want situations where you want to use it on your lap - airplanes, airports, coffee shops, your couch, etc.
No that people are moving to a hybrid in-office/at-home work environment, and companies are going to "hot desk" models I want something maybe a bit heavier than a laptop, that I can easily transport from one desk to another another, and not have to spend a bunch of time hooking it up when I get there.
That is something really nobody makes.