You can look back on the test netting for years, the population has always been there and always will be. People caught them in the winter, but not to the extent they do now. But, you have to remember, there were very few people out fishing back then. Even when the walleyes were abundant, there was not 1/100th of the people fishing the lake that there is today. Even at the crappie peak, there are lots of people that drive all the way up there and do not catch a fish.
It was the abscence of predator fish and the perfect spawn that created this boom. We may never see that again, but we will see the walleye population decrease, the perch population increase and another huge year class of crappies in the future. The lake will go back to more balanced, but the crappie fishing will still be good, we just need another good spawn.