Keep in mind that there are all sorts of mixing rooms. Music mixing vs. theater mixing, and the type of mixing that each place does (hip hop vs. country as examples).
Most mixing rooms are pretty small. Less than the size of an average living room or home listening space, plus another CRITICAL aspect is that these rooms are treated and good money spent on soundproofing, things that most home users don't touch.
I see what you are going for. If we are trying to simulate what the mixers intended, then why not duplicate their equipment, but again, the room becomes the issue at that point.
Lastly, I know that some mixing studios are larger, and such, but many are as I described above. Oh, and as Chris mentions, they don't all use the same brand or model of speakers.
Sorry, not trying to burst the hypothetical thread bubble.
2-M60s, VP180, 8-M3s, SVS 20-39PCi, DIY Sub, 8-Shakers, JVC RS45, Anthem MRX-1120