Commentary from MRBOWLING300 found on a bowling forum from 2013:
What was the downfall of Mark Roth? He basically disappeared from TV in the late 80s. His last title in the 80s was Buffalo 1987 (299 game), and it wasn't until 1995 until he won his 34th and final title in the Toronto area.
He was born April 1951...so he was only in his late 30s, in the late 80s, when he dropped off. It was still before resin. So, it's hard to buy the theory that he dropped off like Holman after resin...although once resin came along, that might have hindered Roth further.
But from an age perspective, late 30s is not very old to be losing it, especially someone of Roth's talent, on the national level. You certainly don't see that today.
I believe he was sucessful on the Senior tour, and then for awhile, he dominated the Generations tour...so post 50, he was still a force.
Maybe the field at that time, especially with the onset of the resin in 1992 brought everybody else up to his playing field? Maybe the years of smoking, caught up to him at that point in his life..and contributed to his drop off?