Another great article Brother Mark! Funny, I guess I started wrestling right on the cusp of significant changes in the sport, so a number of the elements you described - Resilite bonded,non-porous mats vs canvas, removeable covers, singlets vs wool 3 piece, 8 minute collegiate matches and 9 minute international matches, the rarity of post season wrestling, the "black-point" system of international bracketing, true sportsmanship after a victory, Chuck Taylor Converse
Wrestling Shoes (all white or all black, only Dave Schultz or such studs wore "Onitsuka (later Asics) Tigers"), Mats with Square boundries, introduction of the international tech fall...were part of my introductory wrestling experience. All of these were part of my first 4 years of wrestling from 1976-80 and it felt like the sport was very progressive. Very exciting times! . Little did we know how many more important changes (Olympic weights cut from 10 to 7 classes, 1/3 of the collegiate, teams in each division eliminated, rumors of cutting greco from the olympics) were on the horizon that made the uniform and mat changes seem almost joyful!
Again, a great article Brother Mark and thank you for passing the history from one generation of wrestlers to the next. The ancient and honorable job of history story-teller is well cared for in your capable hands my friend!