I was watching a youtube episode on Walleye and it was right out front of my cottage in the north bay, I have been catching them up there all about 20" and a few weeks ago got my biggest at 24" in 6-10' of water. Got one Friday near the park 21" long and they seem to be a bit meatier this year. Beautiful colours and they all go back.
I think the main thing is people keep walleye more than other fish. And lots of people don't care about the slot. Ive seen people take some big walleye out of Kawartha lakes ignoring the 19" slot limit. To some people they don't know there is a slot and they just catch it and eat it. But these are also the same people who will eat musky if they catch them.