Compression

Every dyno show I see where they start at 3 or 5k because 'lower doesn't matter' seems to stem from a lack of desire to tune down there. They just throw more converter at it as it's dripping fuel from the pipes.
I can't speak for the dyno shows but it could be a matter of what they think the veiwers want to see and having to choose what to put in and what to leave out.