I think generally most of Lake O is just not great habitat for them and they also have too much competitive pressure to deal with. Erie is rocky and fairly stable in depth and temp. You also have very little pressure from other apex fish in there, with only a few trout and pretty much no salmon.
Lake O is a mud pit with almost no weed cover as it has a very smooth shoreline with few bays and coves. It gets deep fast for the most part and is subject to major flips, flops, upwellings and other things that make it a rough world for fish that aren't ready and willing to travel LONG distances as need be. Trout and salmon and fine in this world. Walleye, pike and even bass don't love it which is why the population stays much lower outside of the tribs for these fish. Ambush preds tend to pick a spot, with cover, and use it to feed. Lake O doesn't have much cover and no reliable spots.
That is my take.