I'm not sure how many browns are in there or what the diet is. I wish I could find some pics of trout that were caught on lurers almost their own size. A big brown may get full on 1 or 2 trout? I don't know. How many big browns are in the deep pools that stalk at night?
Some photos from Bennett show some pretty large browns that look stuffed. They could be bottom feeding on the cleaned fish and not taking a toll.
Nothing scientific other than some guides mentioning - "it's a good thing they stock rainbows, otherwise there would not be any with all the brown trout". Just their opinion. The browns would be a great cleaning system if they only picked up gut piles.
I missed the DNR report they would be stocking less. Regardless, any day on any stream, I really can't complain.