You're in the financial industry, so this is a topic you should have a working knowledge of, but most don't.
Let me nutshell it for you.:
Corporations are buying back their own shares like never before in history, we're talking trillions of dollars spent on buying back their own shares, yes TRILLIONS. Corporations are "Price Insensitive buyers" meaning they don't care that they're paying sky high share prices.
In fact, that's the goal, since exec bonuses are tied to share price, not company performance. Do you understand the game being played here?
Goose the stock market to crazy levels through share buybacks, and yes, when every major corporation is buying their own shares like mad, the stock market rockets, obviously. Execs get big, big bonuses for high stock prices, and regular employees get laid off in order for the corporation to be able to afford more and more share buybacks.
You say this can't happen because it won't work long term? True, it won't. This isn't done for long term success of the company, it's a way of emptying out the corporations before the mother of all crashes, while maintaining an "All is well!" for the average person, who thinks the stock market represents the economy.
It does not, because the stock market can be manipulated, as I have just explained, so it is possible for corporations to be flat broke due to spending every dime(and borrowing billions)on their own stock, while their share price is in the stratosphere.
Get it? It's a con-job, and it won't last. One day it will end spectacularly with a crash that will make 2008 look like child's play.