Interest rates almost everywhere are set by central banks, not markets, as you imply ("there is a surplus of savings in the world, hence low interest rates").

What you are talking about (money chasing already-overpriced assets) is caused by near-zero interest rates, with an elite having access to low-cost leverage looking to invest that money.

There is a huge problem of _debt_ in the world, government debt, private debt (if you include the student loan debt), etc. Not only is it huge, it is also growing quickly [1].

[1] http://www.forbes.com/sites/mikepatton/2014/09/29/the-seven-...