I'm not sure what made "screen" integrate the two separate pieces of functionality - you can use something minimal like "tio" for serial port access and it's much more elegant.
It's not separate functionality. The back end (so-called "master" side) of a pseudo-terminal is almost (bar initialization of line speed, hardware flow control, and framing settings) indistinguishable from a "null-modem" call-out serial port or parallel port terminal device. Write a software terminal emulation program for the former, which of course is what screen has, and you already have one for the latter.
In theory you're correct, but by that logic you'd also have to add ssh (probably by far the most common way of connecting to a remote terminal today). I guess you'd end up with something like mobaXTerm which is a valid approach for sure, but doesn't compose as well.
Personally I live by the maxim "if it can be separated without significant drawbacks, then it should be separate" but GNU tends to see it differently.
I dont think you understand what a terminal is. What you’re talking about is a shell running in a console. What we’re talking about is the terminal to connect to the console serial port running the shell.
