Technically, I don't think that's true. On average wage growth is slightly above inflation, and growth has been pretty broad and sometimes even better at the bottom end of the income distribution than the middle and top.
But "wages" for top income earners isn't everything. There are a lot of high income individuals that aren't paid traditional W2 wages, instead getting compensated in stock and assets. Those assets have seen large growth, and those that own a lot of it have seen their wealth grow tremendously in the last 8 years. That is fueling income inequality and distortions in the labor/captial balance (IMO).