True, but many of these "birds in the bush" are already available "in the hand".
Both of the camera bodies (A900 and A700), the 70-300G SSM lens, the 24-70 f/2.8 SSM Carl Zeiss lens, the 16-35 f/2.8 SSM Carl Zeiss lens, the 70-400 f/4-5.6G SSM lens are all now available.
PMA should see a few more. The system is building up strength like a gathering tsunami.
The Sony system does not have the lenses I need. Nikon does. Canon does. Period. No doubt for some the Sony system is the bees knees. But they have significant weaknesses.
The advantage here is that these are all ultra-modern 2008 designs, with all the design advantages that go with it, unlike competitive products whose mainstay are relatively older designs/products who are starting to show their age, under the unblinking glare of high resolution FF sensors, especially in the areas away from the peachy center.
That sort of nonsense belongs on dpreview. To show you how silly that statement is, are you aware that many of the second hand Nikon lenses that go cheap on FleaBay are first rate performers on FX? Apparently the ~30 year old 75-150mm F3.5 zoom works very well on a D3x. They go for ~$100. I have one, and it is excellent. The 'old and past it' Nikon 17-35 F2.8 zoom performs very well on the Canon full frame cameras.
I could also mention that full frame is not new and high resolution fine grain B&W film has been around for decades.
And you clearly do not know that most Nikon pro grade lenses are very recent designs. Tilt shift: released in the last year or two. Long telephoto primes: released in the last year or two. 14-24mm zoom: released in the last year or two and with no equal from any other company. 60mm and 105mm micros: released in the last year or two.
And I hear that Canon L lenses are first rate including the supposedly old and hence past it ones.
I am sure Sony marketing like what you say but it is nonsense.
The downside in the Sony system is that for folks who need specialized lenses like tilt/shift etc., there are none available (till date) in the Sony lens range, unless one is willing to shell out significant amounts for Hartblei T/S lenses available in the Sony/MinoltaMaxxum/Alpha mount.
At present, no D700 class camera, no 200mm micro, no tilt shift, no 200mm F2, no long primes, no long pro zoom, those are massive gaps.
I hope that Sony fills those gaps so as to kick Nikon and Canon up the backside and keep competition alive.