The US vs. the Rest of the World

I'll admit that the latest fall in the US stock market was catalyzed by higher long term rates. But the valuation mismatch behind it also deserves discussion. Basically, the US has gotten very expensive relative to virtually all other stock markets in the world.
Here's a chart of VTI, Vanguard's broad based US ETF divided by VXUS, Vanguard's everything in the world except the US. Dividends are reinvested in both.

This is a spectacular chart! the US has outperformed by exactly double since the start of 2011. Moreover the outperformance has been 16% since Jan 2018.
There have been good reasons for this. First, the US dealt with the detritus from the financial crisis sooner and better. European banks are still not out of the woods. Also, the US economy is the most dynamic in the developed world, and the difference is growing. Finally, the incipiant trade war will likely shift growth from EM to the US. But still. You have to wonder if the market has simply gone too far here. I think it has.
Even if there is no crash in the US, I bet that there will be a long period in which some of this gets reversed. I'm primarily a bottom up investor, but I have made portfolio changes. I have written LEAPs against much of my US equity position. Left the non-US part alone.