Why exactly does rptv tech fall short of LCD and Plasma in terms of sheer PQ?

[Steelmaker]

I always hear reviews say things like "DLP is the best bang for the buck if you're wanting a large tv for a good price." However I never hear anyone just simply say DLP sets look fantastic on their own accord, regardless of price and size. They always have to throw in the obligatory "it's great if you're too broke to afford a high end tv."

Besides the obvious shortcomings on DLP sets like poor viewing angles, not being able to hang on a wall, and bulb replacements (though the newer Samsungs don't use bulbs) where exactly do they fall short when compared to plasma and LCD and can rptv technology ever theoretically match the others?

I guess the reason I'm asking this is because I currently own a 60" Sony SXRD and to be honest, the PQ still impresses me two years later. When it comes time to upgrade, I want to understand why the other, more expensive technologies are better and worth spending more money than what I spent on my current set. Keep in mind that known "issues" with rptv's like not being wafer thin or the viewing angles being poor are completely non-issues for me. I want someone to go beyond the obvious stated cons for rptv's and explain WHY plasma and LCD have better PQ.

If Samsung and Mitsubishi are still making rptv's when I upgrade, I'm going to be hard pressed to find a reason to change technologies when I have been completely happy with the one I have already. I guess I'm just seeking better understanding (in a nutshell explanation).