+1It's always interesting to see reference to "newer, higher pressure tires."
Correct me if I'm wrong, but in most cases this is the difference between radial and bias-ply tires.
In most cases, the tire specified for your bike is one or the other but never both. If that's the case, there simply aren't "newer, higher pressure tires" applicable to your bike.
(One exception may be Conti's new radials directed towards Airheads and maybe old Ks, but haven't studied that. They have just been introduced this summer.)
And, the numbers on the sidewall are completely meaningless except that they indicate the maximum pressure safe to use in this tire. This has NOTHING to do with BMW's or the tire manufacturer's recommended pressure for your particular bike and load conditions.
Except for the following, that is ... A recent presentation at our dealer by a Metzeler tire rep featured the notion that if your goal is to maximize tire mileage, i.e. tread life, then you should indeed run your tires at the maximum pressure indicated on the sidewall. It's printed a little less strongly in Metzeler brochures, too. This of course, is NEVER the basis for BMW's pressure recommendations for your bike and most obviously may involve some handling and/or comfort and/or performance compromises. I'm not doing it, as my goal is fun associated with riding and for sure not carefully saving every penny and diminishing the fun. I mean, if it's about only tread life, just never ride.
If you've a current model BMW, recommended tires by brand are listed at BMW's website. These charts don't go very far back as regards discontinued models IIRC. There is, not completely coincidentally, sometimes not sizes for older bikes in the latest/greatest tire models, and the older bike guys then use the older models anyway. The notion that perhaps tires (brands) not on the recommended list somehow require completely different pressures is a bit of stretch in logic, too, I think. Look for that brand to publish something instead.
Bottom line, I think, is that BMW's recommendations are simply fine and are good for a long time. If a tire manufacturer will publish in writing or on its web page that they indeed have different recommendations for you, then pay attention. There's not a lot of data provided by various internet contributors to back up their claims when it comes to varying from BMW specifications, and they should direct you to data rather than their opinions and unscientific observations. I know for sure that I've never seen specifically published by a tire manufacturer that pressures recommended by BMW in, say, the 1990s or 80s or 70s have been superceded by "new technology." I'd love to be directed to it.
You can also rationalize that somehow BMW's specifications don't apply specifically to you because you must weigh something different than their average rider or something like that, but I'd instead conclude their figures can be recognized as covering normal variations. BMW's figures are quite fine and it's not really about demonstrating that you know more than they do, is it? When it comes to "voice of experience," nobody tops BMW.