Because that's like teaching perl cgi in a web dev course.
"perl cgi" can be not used at all, but today's x86 machines still boot in realmode and you can already do a lot of interesting things there.
while there is a clear lack of good introductory articles on how to create minimalistic kernels using a stack like Core boot, uefi, TianoCore
That could be explained by the massive increase in complexity that UEFI entails compared to BIOS. Presumably it is only after you have gotten everything working with the BIOS that will prepare you to tackle UEFI; but speaking as someone with many years of experience with the former, and even read the BIOS source listings from the original IBM manuals, the UEFI spec was still ridiculously dense and if I were writing my own OS I would definitely choose the BIOS.
"perl cgi" can be not used at all, but today's x86 machines still boot in realmode and you can already do a lot of interesting things there.
while there is a clear lack of good introductory articles on how to create minimalistic kernels using a stack like Core boot, uefi, TianoCore
That could be explained by the massive increase in complexity that UEFI entails compared to BIOS. Presumably it is only after you have gotten everything working with the BIOS that will prepare you to tackle UEFI; but speaking as someone with many years of experience with the former, and even read the BIOS source listings from the original IBM manuals, the UEFI spec was still ridiculously dense and if I were writing my own OS I would definitely choose the BIOS.
Related reading from someone who has written his own, now rather famous, OS: http://yarchive.net/comp/linux/efi.html