I don't worry about that at all.

The risk is that there is so much in index funds that the valuations of companies will become distanced form what they're actually worth.

The likelihood of that happening given how much money there is to be made in finding the inefficiencies in the stock market are, in my opinion, very small.

Passive investing is nice, but I have seen few good articles about drawing down when retirement actually hits.

Index funds are therefore the next bubble?

Assumptions:

* index funds are larger and larger share of investing

* Median Baby boomer about 63

* 1/2 Americans in stock market

* In 2017, over 62 million Americans receive SS benefits

* US Adult Population 247,773,709 = 123M in stock market

* Only 25 M generation X

* Millennials don't invest in stocks http://www.businessinsider.com/why-so-few-millennials-invest...

Conclusion Drain of stock market as sellers begin to out number buyers

This ignores just how skewed towards the rich stock ownership is. The liquidation of stocks owned by the middle class will not move the needles much. And the very rich don't need to liquidate their stocks to maintain their lifestyle.

or maybe public investable assets? Too much money chasing too small a pool of assets? There are also a lot of private assets that could be superior investments, but average folks do not have access to.