The 650 has two pedals, One tibia and one main. No crescendo and, to be honest, most owners hit the tab that linked main and tibia together on the left hand (foot?) pedal. Some smaller Conns had 'stereo expression' where the main level could be set with a slider and the tibias controlled via the single pedal. I'm not sure that owners used that much either.
I can't see that it would be an easy job on a tonewheel organ. Or other organs, for that matter.
As for why it didn't appear on home organs. Complexity and cost, if it were possible at all, and the fact that most amateur home players would not have used it anyway. It was on some of the TPO's I used to play, but I rarely used it. And that's as a pro, I think the average amateur will tell you that they have enough to do with two manuals, pedals and a pedal for dynamics - without adding something else into the mix!