There is a lot more to the economy that is out of the control of monetary policy. Companies and large organizations (Apple is a prime offender, hoarding $70B+) are sitting on a lot of cash. They are unwilling to invest it, spend it, or even to return it as dividends. Instead, they buy large amounts of treasury bonds* (which has pushed yields on them to unheard of lows).
The obvious solution to that, then, would be to use fiscal policy - to spend the money that is being dumped on the treasury at rates well below inflation. The treasury is paying negative interest, in real terms (and for a very brief period, in nominal terms!). If private entities won't spend it, the government should - provided they can step back, and reduce the debt when things get going well again.
Strangely enough, more deficit spending might be the solution to a problem caused by too much deficit spending to begin with.
One other caveat; there can be still more causes to unemployment that are not monetary in nature. Labor markets are notoriously inflexible.
*: I don't mean to imply that Apple literally holds treasury bonds (though they might). Apple might have its money in a bank, and the bank might deposit the money at the fed, or buy treasuries itself, but the net effect is the same; the money sits somewhere, unused, where the government could use it. In fact one suggested solution was to stop paying interest on federal reserve deposits, or even charge a negative interest rate on deposits above a certain threshold.
