Um.. Under communism you can literally do absolutely nothing for the economy and still get paid the same as everyone else. Don't tell me no one will leap at that opportunity or that "social shunning" is enough of a deterant. The slackers will simply band together and form a community of their own occasionally venturing out of their shanty town to consume other people's produce.
I'm all for some of my tax to pay for orphanages etc... but communism is ridiculous.