In all cases at all times professional production is about "what's the best way to get the best result considering all factors". So Nolan flipped a real truck but Cameron didn't breed actual 7' blue mutants. Quality of result vs hour/dollar consumed is the metric. The smart filmmaker uses whatever best solves that equation regardless of whether it's cutting edge or blunt instrument.
Absolutely. And there will be times when "lighting in post" will even be a useful tool.
But you don't dismiss the orchestra just because you have a really bitchin' Casio keyboard.