That's definitely part of it; climbing harnesses tend to support you in a position that's great for suspension trauma, but involves a pretty inconvenient rope.

That's definitely part of it; climbing harnesses tend to support you in a position that's great for suspension trauma, but involves a pretty inconvenient rope. They're also waist-and-hip only, and while they'll reliably hold a climber through a flip, it doesn't sound great for chaotic, confined-space falls where you might stay upside down. The newer generation of construction harnesses are still back-clipped and full-body though - a short strap runs from the waist to the back clip to redistribute weight without normally being in front of you. Presumably getting that working smoothly and safely was an extra engineering hurdle, but I'm still surprised harnesses went so long without even including waistbands.