Okay, I think I've got it now...
The automakers spend millions of dollars in R&D to determine the psi rating based on a multitude of factors (ride quality, handling, economy, wear life, wet handling etc) and therefore they are right, but the tire makers also spend millions of dollars in R&D designing specific tires for specific applications, therefore the auto engineers are smarter if it's 1980 but the tire engineers are smarter if you are driving backwards singing the theme-song to "The Fresh Prince of Bel-Air".
I've learned that it can be a hazard to run your tires above 35psi but as long as you follow the max pressure but don't tell anyone else to do that then you're fine because no two people here are going to do the same thing and agree on it. As long as you have air in the tire you are fine but you can't have too much and you can't have too little so make sure you listen to automakers on days that end in 'Y' and listen to the tires makers on all days that are sunny. If it's raining though don't do anything until you make sure that the car is in a good mood or your tires disappear altogether.
I've learned that chalk can tell you how much of the tires you use (which I'm definitely going to have to experiment with, thanks supradjza80!), and I've learned that tires are a big round rubber spring that you will need to tune in conjunction with the rest of your suspension set-up.
Does that sound about right? So basically what you're saying is that I need to play around with my car and find a set-up that works for me, with my suspension and my chassis on my roads with my particular driving style...
Okay, I think I've got it now.