Based on my experience (SPG Plat for 3 years), I would say your experiences were pretty normal for stays within the US. Starwood needs to get better at educating hotels about these benefits; if you want what you are entitled to, you need to fight for it far too often. There are many threads here about hotels that refuse to upgrade to suites even when they are available on the SPG site. Platinum amenities are not offered more than occasionally, and when they are offered, they are often not delivered (points not credited, various food items not sent to room) In general, Platinum status is, in my experience, just not that big a deal if you are not willing to spend a lot of time and energy getting what you are entitled to.

All that said, I think SPG is, for me at least, by far the best of the frequent stay programs. If you consider the whole package (SPG Amex, opportunities to use points, hotel quality and variety), I don't think there is another program, including Hyatt, that can come close. Nobody else has the range of upscale properties that SPG does, and the points you earn with the SPG Amex, when used wisely, are far more valuable than just about any other rewards card out there. I have status at IHG, Fairmont, and have had it at Hilton and Hyatt -- for me none of these come close to SPG.

The bottom line for me is that Platinum status is a nice bonus; when I get something from it, I'm happy, but I don't expect much. The rest of the program, and the hotels themselves, provide the reason for staying with SPG, not the status.