No, Punk shows did NOT start pitting. They started a Ring Around the Rosie. Thrash pits are NOTHING like the Punk Circle Dancing.
I'm only 34, but I went to DK, Black Flag, GBH, Exploited shows in the VERY early 80s, still near the death of that scene, but I was there. When TRASH came on to the scene at that time, the PITS were NOTHING alike.
Punk pits is some banging around, but mainly just dancing. As a matter of fact, the first time I brought a HARDCORE PUNKER to an EXODUS show in 84, he practically shit his pants. He said he'd never seen anything like it... And he was old-school was into hardcore dancing (which is the modern equivilent to a Punk "Ring around the Rosie".
The Pit was just Violent... he had never seen a true FRENZY either. Hell, I haven't seen a real FRENZY since Testament in the mid 90's.
Most of us that are hardcore thrashers are too old to do that for any length of time now.
And pits today aren't even a shadow of their former glory... even when the big thrash or death metal bands come around...
People don't pit at Black Metal shows... guess they're too involved with headbanging and making sure their corpse paint doesn't come off...