Savers are useless non-contributors. Not that there's anything wrong with saving, but economies of scale don't depend on it, and so there's no economic justification to encourage it.
You cannot be more wrong. Saving is simply deferred spending. It's spending later vs. spending now. You could argue that incentivizing spending over saving is transferring prosperity from the future to the present. In the end it's a zero sum.
More than that. Saving is required for capital formation. Many enterprises and much innovation depends upon capital formation. Without capital formation it is much closer to net zero-sum. With capital formation, it is more like win-win than it is without it.
Yup.
http://en.wikipedia.org/wiki/Savings_identityThe caveat is that not all investment is actually useful investment. For example, building up inventory of unsold goods is considered investment in accounting terms, even though the goods may not be wanted and may never be sold.
That said, you do need savings for there to be (good) investment.