The gent who designed/invented SOP sold it to I guess it was Summit. He still comes along to the Harrisburg Sport Show. Always enjoy talking to him.
I noted some years back the double metal buckle and slip thru-twist arrangement that replaced the plastic buckles.
Larger companies like Summit have huge liability problems and risks, so their team of Legal-Beagles up the Anti and make everything as near idiot-proof as possible.
Taking back a lightly used harness to refurb with new hardware would be the same as assuring the integrity of the older style material. They don't know it wasn't stored in a sun-baked locker and ready to fall apart...to test it again would subject it to more stress and if it ever failed, it'd by a huge claim in the making.
These companies are up against the liberal trial lawyers and the people who let folks claim horrific damages for being stupid...so companies protect themselves in what seems "user-un-friendly" ways.
Silent Slide is a company that makes a simple safety belt. He also comes to Harrisburg adn has some intriguing research literature he shares on the effects of full body harnesses that refuted some of the 5pt harness safety claims...but echo what Coilspring espoused above! They're designed to keep you from hitting the ground...not designed to prevent injury...
I had a chest-only harness once and came out of a tree with it when a climber came apart... (operator error). I had read you have 3 min before chest compressions will make you pass out.
I said a prayer, made a plan and got out of a fix... but I was one shaky boy till it was over, both from nerves and from exhaustion. Thankfully that was 20 yrs ago and I was a lot younger/stronger.
Never trust a harness to save you. You're head is better, but the harness is great back up!