I think what really happened is that as Carmack became more senior he got more and more out of touch with the technology. So I don't understand why people still refer to his words as gospel, especially since the domain he's now in is so far outside of his original specialty.

Doom 2016 would've never been possible with him at the helm. Then again now they're adding viking bullshit to it so design by executive committee kills yet another beloved franchise.