> Keynes « center piece » is not manipulation of money supply.Yes, it is. Keynes said at one point that the government printing dollar bills and burying them for people to dig up would be a valid form of economic stimulus.
> This extreme monetarism you describe is... Friedman’s!!!
Milton Friedman did not advocate anything like the arbitrary manipulation of the money supply by the government that is practiced by the Federal Reserve. (He was in fact a consistent opponent of the Federal Reserve; he thought it should be abolished.) He advocated tying the growth rate of the money supply to the growth rate in real productivity, with no discretionary element at all.
> Ultra liberal economics lead to accumulation of wealth by few super riches
No, the government printing money and giving it to a few favored parties, which is exactly what the Federal Reserve does and always has done (the favored parties have almost always been financial institutions, no surprise given the background of most Fed members), leads to accumulation of wealth by a few super riches.
> This happens to be one of the reason the Roman Empire fell because all this money could not be spent on keeping the army in working conditions.
I don't know where you're getting your history from, but it's wrong. The reason the empire had trouble paying for a competent army was that it had debased the coinage so much that people were refusing to take Roman coins as payment. It even got so bad that the Roman government itself, knowing that its coins were worthless, stopped accepting them in payment of taxes and insisted on payment in kind instead.
The emperor Constantine managed to get hold of a large supply of gold bullion and used it to mint new gold coins, which were accepted in payment of taxes. That helped for a while as the empire could use these to pay the army and the civil servants; but many people could not afford to buy the new gold coins and therefore could not pay their taxes, so the improvement didn't last too long.
It also didn't help that the size of the army and civil service kept increasing, for no tangible reason, which just increased the tax burden.