That's why they call it fishing!!
I do agree that the fall bite is better on the lakes than in the rivers, but like has already been stated I think that comes from fish moving up from the depths of summer into areas that are easier to target them. Plus the water has cooled a bit so they have a little more energy to chase and eat. But it's not a guarantee either. Fall fishing can be some of the toughest fishing you will find.
But I don't buy into the fact that in the winter months all the fish go deep. I have too many good days fishing shallow in the winter to ignore that water. You might not see them on your graph because they are sitting on the bank. One of the best days of fishing that I have ever had was one winter on Pomme de Terre. It was cold. 28 degrees when we launched, spitting sleet, surface temps steady all day at 44 degrees. We started fishing deep and caught a few fish. But it really got good when we were throwing spinnerbaits right up on the bank and burning them back to the boat. And this wasn't in one concentrated area. We caught fish all the way from Wheatland ramp to Bolivar landing. It was crazy good.
Sidenote, maybe it's just the fish in that lake. I also caught a ton of fish one very hot summer day fishing the same pattern. Spinnerbait on the bank. Air temp was pushing the hundred mark and the surface temps were in the low 80's. Won that tournament by a substantial margin.
We will never truly understand why a fish does what it does. And sometimes we get too hung up thinking they are going to be where we "know" they will be. That's when failure can set in and really punish you. Now I just go when I can, catch what I can and have a smile on my face every time.