Not one person has mentioned the change the was the most revolutionary and started the technological trend to ever more aggressive ( high friction ) balls. The change from lacquer lane finish to epoxy urethane lane finish in the early 70's started this all. Prior to urethane lane finish polyester balls had been around for 10 years yet nobody saw any real advantage to using them over the hard rubber balls of the 40's 50's and 60's. On urethane finish, Don Johnson and others found a much better ball reaction from the polyester balls, particularly Columbia white dots, than from rubber. They also discovered that the softer the shell the better the reaction. Columbia came out with the super soft shore d, and then the yellow dot ( softer than white dot but harder than shore d). Scoring began to go up dramatically in the late 70's at all levels. In 1981 the urethane ball was introduced. It was no softer than polyester, but bowlers discovered that it could be sanded down to 400 grit and still skid through early oil but come booming off the dry. Scores continued to rise as the ABC mandated shorter oil to keep lane men from using oil to steer the ball to the pocket. Wrong move. The new breed of bowlers that was coming out by 1980 were just looking for some head oil and a lot of swing area which the short oil walls of the 80's provided. Again, scores continued to rise. Lots of league bowlers pushing 230 by the time the resin ball came out in 1992. Resin enhanced urethane created friction more efficiently than pure urethane, and allowed strokers to rejoin the scoring parade that had been dominated by power players for 10 years. Resin also soaked oil off the lanes and created the need for higher volumes and longer oiling than was needed with urethane.
Modern lane machines and more consistent synthetic surfaces certainly had an impact on scoring, but it was incremental compared to the progress in ball technology and the harder surfaces. Biggest factor of all is that bowlers today are much better than they were 30 years ago. I am 69 years old, and am not the player I was even 10 years ago, but I have no doubt I could go back to the conditions of the 80's using the equipment available at the time and score as good or better than I did in my prime simply because of changes I made to my game, and knowledge I have accumulated to offset my physical decline.
Bottom line in answer to the original question, I might outlaw urethane in 1992, but not because of its scoring, rather because of the way it destroys lane patterns. We have the ability today with the modern machines to put out a variety of challenging lane patterns yet high rev players blow the patterns up so fast you cant run a long format tournament anymore.