I think it has less to do with C and POSIX, and more that Unix from day one was multi-user, you can't have someone "bitbang" hardware when there are multiple users accessing.
Also, i think perhaps you conflating issues here.
While sure they may be more interested in the GUI (though you will find plenty of TUI programs in the Unix world, and even some in Windows that has been inherited from DOS) the newer generation is less likely to be interested in the actual hardware beyond that it works to run their precious "apps".
And IMO the demo scene were largely "dead" by the time Linux come on stage anyways.
This because the fixed hardware models of the C64 and like were being supplanted by the mix and match PC, where the only commonality is the BIOS and the CPU ISA.
Also, i think perhaps you conflating issues here.
While sure they may be more interested in the GUI (though you will find plenty of TUI programs in the Unix world, and even some in Windows that has been inherited from DOS) the newer generation is less likely to be interested in the actual hardware beyond that it works to run their precious "apps".
And IMO the demo scene were largely "dead" by the time Linux come on stage anyways.
This because the fixed hardware models of the C64 and like were being supplanted by the mix and match PC, where the only commonality is the BIOS and the CPU ISA.