It was required to produce silver dollars to back the currency.
Remember that World War I was over. Minor coins were not needed in 1921 and 1922 as much as in 1917 or 1918.
1922? Didn't the Philadelphia mint experience a fire that year? No cents were produced.
Only Denver made them.
As for all mints :
Yet another example of why history and coins are linked.
I feel sorry for those who do not learn the history.