Actually, it's not the kernel, it's the fact that Unix has a much greater legacy than just a box with one user and a keyboard attached to it. In the Unix world, a keypress doesn't just diddle a few bits on a hardware port which you poll with a system call. It's communicated as part of a complex protocol implemented by the terminal you use. Applications read a raw protocol stream from STDIN and are expected to interpret it; this is where termcap or friends and all that devil's work comes in.

I understand the whole shebang just well enough to make it work and then supress any memory of it. :-) Things seem to have gotten far, far better in this respect in recent years, though, with most stuff working out of the box. The effort this takes on the distributors' side should not be underestimated.

Your post is partially correct in that the Linux kernel does implement a terminal for the text mode consoles, though.

Makeshifts last the longest.