Why is it? For example the lakes like Bitter, Waubay, Whitewood, Devils Lake & others consistently produce. While others like Lake Vermillion, Wall Lake are the dead sea, or produce sporadically.
I fish a lot of smaller lakes/ponds. Same thing, some produce consistently. I know there are good fish in the non productive waters, I've caught them, just not with regularity.
25 years ago Lake Vermillion had good Perch & Crappie fishing. Today I go by & not one person fishing!
A few days ago I was on a small lake, looking for Crappie/Bluegill. Drilled & moved a lot & put a few on the ice. Three others showed up & drilled & moved at least as much as me. They put a few on the ice too. Not near enough for the effort we put in.