From the department of picayune fact-checking: The U.S. Army has 419,155 bayonets in its inventory. The Marine Corps has about 195,334 bayonets (and has plans to acquire 175,061 more).
That's a total of 614,489 bayonets with 175,061 to be added. Keith Koffler adds everything up:
Given that there were about 200,000 men in the Army and National Guard in 1916, according to National Review, that would mean that there are three times as many bayonets today and probably will be at least four times as many than before World War I.
So, there you go.