The main thing to take from Johnmoe's picture is that it's not the antenna. There's no yagi being pointed anywhere, or away from anything.
It's all about the method used to demodulate.
If you use the correct method, you get pretty damn good coverage, even with a very basic antenna.
If you use the wrong method (e.g., C4FM instead of CPQSK), you're going to get crap results.
Uniden and Whistler need to wake up, and so do their customers.
Of course, this does beg the question of what Johnmoe could pull in if he had a nice (omni) gain antenna with a low-noise preamp, correctly filtered of course...