I don't entirely agree. Projectors will less than world class contrast can display very good shadow detail. The Sony 40es is known for good shadow detail with a on / off contrast of only 5000:1.
I think the factors airscapes mentioned are more important. Hell an incorrect brightness setting alone can kill shadow detail.
What don't you entirely agree with? If 2 projectors are calibrated and one of them has much higher native contrast, it will do better with shadow detail. Sure a poorly calibrated projector can crush shadow detail.
I shouldn't have used the term "top notch", as that implies subjectivity, when the contrast can in fact be objectively measured. Shadow detail is just a function of proper gamma tracking and available contrast.
I guess I misunderstood this thread. I thought op wanted to know the science behind it, sounds like they just need to properly calibrate their projector/gamma as the bulb dims.
As the bulb dims the entire visible light range will dim, crushing shadow detail to black in the process, you will need to adjust the brightness, and gamma controls to compensate (recalibrate).
The Sony's and Epson 5000 series (especially ub) will provide better black level, allowing you to see more detail in dark scenes with a lower overall light level (aka dark scenes will be darker). If you don't set the brightness and gamma correctly though then you will crush the shadow detail regardless of available contrast.