This is confirmed correct. I just got a set of wheels off the PBB for my 78 FJ40. Like a dumbass, I didn't check the backspacing, just the bolt pattern. When I torque down the lug nuts, the steering arm gets caught in the inner part of the rim and the wheel won't turn.
Actually, by the book, 3 3/8" is the number, but thats not the point. Too much backspacing will rub on your steering arm and tie rod end, obvious problem. On the other hand, lesser backspace, further exaggerated by excess width, causes "scrub". In offroad this translates to that painfull experience of having the steering wheel ripped from your hands. It also causes higher stresses on wheel bearings, axles, steering knuckles, steering components, etc. Most of us opt for the wider wheel base, increased floatation and other benefits. We have nice "band-aids" like steering stabilizers and power steering to cover-up these ill side effects.
It's best to stay close to the orig backspace.