Why don't crop sensor cameras have crop weight bodies?

The Canon 7D with its 1.6-factor sensor weighs 900 g with battery --
the Full Frame Canon 5D2 weighs 907 g.

What the hell?

Why aren't the smaller-frame bodies significantly smaller than the
bigger frame models, as used to be the case between 35mm film cameras
and the medium format models like the RZ and the Hasselblad?

The small frame normal zoom for the 7D is the 17-55mm lens, and it
weighs 645 g. The corresponding model for the 5D2 is the 24-105mm, at
670 g -- only 25g heavier.

Put body and lens together and the bigger format weighs only 2% more.
The difference in price is around $1000. But for that extra cash, I'm
getting so much more camera.

The 24-105 lens has a smaller aperture, but considering the size of
the sensor, gives about the same DOF as the 17-55mm lens for the same
composition with both lenses wide open. I can compensate for the
slower speed of the 24-105 lens by dialling in one stop more ISO. I
won't get more noise because the pixels are larger. So DOF and noise
are roughly equal, after making these adjustments.

But the bigger format gives me better resolution. The lens has a 4.4x
zoom, instead of only 3.2x for the smaller camera. The 5D2 is less
limited by diffraction. And all reports suggest the 5D2 produces much
better IQ than small frame models.

All this for a diff of a thousand bucks.

What am I missing here?

Wally