Again, time preference solves this problem. If this were true, everybody would be a lender and nobody would be a borrower out of expectation of more money in the future. Fortunately, people have more desire for money now than for money in the future, which raises the price of the former.
But this hasn't happened in the real world. And besides, a rising value of each unit of money is useless if you lose your job thanks to a sustained fall in aggregate demand.
No. When Spain plundered the gold and silver of Mexico and and Peru, the massive and sudden increase in the Spanish money supply caused so much inflation that it wrecked any incentive to create technological innovations or a domestic industry. Only in the past decade has Spain fully returned to the European mainstream. When Ming Dynasty China experienced a massive influx of Spanish silver (in exchange for tea, porcelain, etc), the resulting inflation contributed to the peasant revolt which led to the collapse of the Ming Dynasty.
Likewise, the gold (or any limited metal) standard is simply unable to prevent massive and sudden expansions in money supply, and periodically adjusting the conversion rate makes it meaningless.
Finally, there will be a huge incentive to short the gold-backed dollar. Such a move will most likely cause high unemployment and a long recession. Congress will haul the Fed Chairman and Treasury officials for grilling every week. Eventually you'll lead to something like Argentina in 2001.
