I think there are two interconnected issues regarding these large fish, especially the lake fish:
(1) There is an incredible amount of food in the lake now. Shad, YOY stripers and sheephead. It’s hard for a SR5 to compete with all that chow. There are giant balls of bait most everywhere in the lake now…enough to darken your entire locator screen.
(2) I think that most people ignore that a significant fraction of these larger predators suspend in the summer. The reason that we don’t contact large #s of them is that they are not relating tightly to structure (drop-offs, humps, etc) like they are earlier in the year. So, if you want to catch them, you end up trolling a grid around the lake until you contact a few. But, there’s a lot of lake out there, so it takes time to find them!
Fish can’t suspend in the current, however, and those resident fish in the river still gotta eat. Those two issues make the river fish easier to locate and to catch, IMHO, than the lake fish as the summer wears on.