I'm not sure where the PM5544 comes in to tell you the truth, I guess the only 'real' way would be to take a real-life 'typical' scenario with a new c64 and... what? An average TV of that era, of a Commodore monitor at default settings (if there's even such a thing) and then use a hardware colour picker to read the values?
No argument, with certain settings the pics on that page look gorgeous, but I've never, ever heard a c64 user saying the machine has vibrant colors

In the old times I remember gatherings at friends' houses, where people would bring their own machines. Understandably I only did this very rarely because bringing my SCART cable was not enough for the CPC to work, but we had MSX, speccies and c64s going around. Spectrum games were very colourful but with a bit of toy-like primary colour quality and cheerful; CPC games were a visual orgasm (whether good or bad). And the c64 had to rely on its hardware scroll and SID because it generally looked so boring.
So.... yes, I do get what you're saying and what they're trying to do, I'm just not sure if it's any relevant. Sure, an artist picks his colours and canvas carefully, and some times he's got the luxury of knowing or dictating how the end product will be positioned (think Capela Sistina). But most often than not, that's not the case and real life conditions take precedence. I'm not sure "how vibrant the colours really are with the proper hardware" is a valid argument in any sense - I don't know, what is the "proper" hardware? My CPC always looked fantastic no matter what tube I threw it to - including my recently purchased 1084S (which I later found out also had the "green screen" button - soooo neat!

)
It boils down to this:
Publisher: -You've got to fine tune your monitor settings, otherwise our game looks like a pile of shit on a pile of mud!
Teenage gamer: -No shit, Sherlock.
I'm not sure I'm 100% successful in getting through what I mean (my migraine du jour doesn't help either), so by all means let's keep the discussion going - your points do provide much food for thought
