I think there's the global maximum vs local maxima argument in favor of doing something too. Why do people ultimately spend time on Facebook? I would say they

I think there's the global maximum vs local maxima argument in favor of doing something too. Why do people ultimately spend time on Facebook? I would say they don't do so because of micro-optimized KPI targeting: they do so because they feel time on Facebook is valuable and makes them happy. If Facebook can't deliver increases in that, then optimizations only take them so far.