The simple reason Beyer cameras with mild AA filters (they almost all have some sort of spatial filter even now, regardless of marketing drivel) don't show much moiré in 2015 is that the pixels are sufficiently small that the resolution delivered to the sensor plane is almost always oversampled.
The bigger the pixels the eaiser it is to see moiré. As pixels shrink, more adept optimization of the rest of the imaging chain is required to excite moiré.
Specifically: with modern 36-50 mpix sensors very few photographs are taken with a combination of lens, aperture, camera support, shutter speed, and focus precision that the sensor resolution is actually limiting. In addition, many (most) subjects do not have high-frequency repeating patterns (e.g., fabric) that make aliasing obvious.
Consequently, there are few situations where aliasing is obvious in pictorial photography when a high-density Bayer sensor is employed. Most photographers don't work close enough to the resolution of the latest sensors to actually excite it in the first place, most subjects don't make the aliasing obvious — even when it's there, and most sensors are not as free of antialiasing devices as consumers imagine.
Put a D800E or an A7R on a heavy, well-damped tripod with a top modern lens, and shoot at f/4 with critical focus under a single strobe (not a set of inexactly-synchronized strobes). Do these things and if you're shooting fabric with the right sort of pattern you'll sure as heck see moiré, and plenty of it too. Even with the XTRANS sensor, which is indeed comparatively immune versus a Beyer sensor with identical pixel spacing.
