The sad truth is that no matter how good the staking is, one good trade can make more NAV than a whole month's stakes.
I agree having 1mil on the exchange is stupid because the volume is not that big that you can take advantage of price fluctuations on such a scale.
But for those that have 100000, maybe even 200000, keeping them on the exchange and playing conservatively is more profitable

I myself decided to keep half my NAV on bittrex and the other half in wallet.

In other news: Just like that, out of the blue, the poloniex ticker started working on my wallet for the first time ever