There are "kits" available that eliminate the hump and make the firewall flat. Kirk Evans for one.
IF you combine installing that kit with installing the Tesla electric parking brake, you can also eliminate the original parking brake handle and mounting bracket.
That will allow you to push the passenger seat all the way back and allow a non-surgically altered human to occupy it.
Why this was never dealt with properly to begin with is an unknown? Might have been simply budgetary? I would have expected that Ford would have insisted on a fix and am surprised that they even approved this terrible design to begin with?
You can't entirely eliminate all projections into the cabin. That would have required a special water pump and that Ford would have never approved so maybe that is the answer?
Whoever the Ford Engineer was on location in Italy made some strange decisions to begin with? For one thing, he didn't want to have brakes that were too good? I suppose that in his own twisted way, he thought that would increase the likeliness of rear end collisions because "regular" cars wouldn't be able to stop in time like a Pantera could and would increase legal liabilities?
Inhaled hallucinogens at the time certainly created unpredictable decisions for sure? They must have still been on the paranoia effect and it hadn't increased creatibility yet?