I think if Gary would have quit pinball someone else would have bought the assets and continued. I know of at least one party that was ready to jump in and there may have been more. Aside from that, I'm pretty sure that if Stern would have quit at some point a new party would have stepped up to fill the void. Who knows what would have happened then.

As far as the poll/question goes, I think Barry Oursler's Space Shuttle came at one of the most critical moments of the pinball industry. I don't want to take anything away from Roger Sharpe's achievement, which certainly boosted the industry, but at that point in time, the industry wasn't in such a bad shape as it was in the mid-'80s. Apparently, at some point no company made any new games for a period of 9 months. I don't think we've seen that in the post 2000 era. Also keep in mind that once pinball got back on its feet, it was Roger Sharpe again to reintroduce licensing into pinball, leading to some of the best and best-selling games ever (and some of the worst as well, but Roger wasn't involved in those). So it depends on how you look at it.