In FDRs day, a gold standard was considered evil by the poor and struggling middle class. So they were happy to see it go. It was not until the 1980s that the treasury allowed the public to buy and sell US gold bullion coins again. I don't think the government has any incentive to seize or buy back all of the gold coins out there, because no one is going around trying to use their US gold coins as legal tender to compete with the unbacked federal reserve notes. The thing that is happening with gold right now is plain speculatory investing that started about 12 years ago. During recessions, people also buy up quantities of silver and gold in anticipation of financial collapse and hyperinflation. The price seems to be trending downward now very slowly.