Found out a cool youtube channel on music production

this guy makes some good points but he totally went off the map with the loudness. since when are mixers responsible for loudness? no even half witted a&r or label rep expects the mix engineer to set final levels, thats what they have mastering for. by his logic, if the client is perfectly happy with the "demo mix" and just wants it louder there's no point of paying a dedicated mixer to "do his thing" and might as well just send it out to mastering.

he makes some points, but comes off kind off weird with the others.
 
I think he means he has to mix it in a certain way to make sure it keeps its vibe and is still loud enough, rather than sending it off for mastering and getting it back loud but squashed and devoid of dynamics.