Difficult to say, although I was paired with one of the dreaded headhunters over the weekend. She was literally taking a Track ball (I believe it was a polished Threat) and maybe laying it down on 15, carrying a majority of what hit the brooklyn side of the head pin. She had two balls on her ball card and neither was the best alternative for the condition we had...unfortunately, because of how she threw the ball it was almost exactly like following the leagues of people throwing plastic dead up the gut. To watch her, I would guess maybe 175 and dependent on strings of strikes and very dependent on lane conditions for any ball reaction. That sort of a bowler does not see the real gap between the THS and sport-compliant conditions
Much of the problem in getting people to bowl on sport-compliant conditions are that it is not explained to them how it will help their game. If someone just goes out and tried to throw the ball week in and week out, they will not benefit from sport-compliant conditions. However, if someone wants to hone their game, and is willing to put their ego aside and actually try to learn new tricks, then the sport-compliant conditions could be viewed more favorably. It is incumbent upon the associations to explain the benefits to their members and as we know, many associations do not do anything of the sort.