Likewise for the Militia Act of 1792. It has the states appoint officers, and has states do other tasks pursuant to the militia, but does not separate out militiaS as multiple independent entities. What the Act organizes is a federal organization pursuant to explicitly delegated Constitutional power, with portions thereof managed (but not owned per se) at state level.
The officers appointed by a state preside over militia members resident of that state. Both, however, serve in "the militia" (singular), which is a federal organization with the President at its helm.
If, as you contend, it was all about "state militias", then Congress would not have been granted the power to organize the aggregate thereof, and would not have had the power to pass a federal "Militia Act" which legislated the organization in great detail (right down to the minimum number of bullets each member must have). The states are granted the power to assign officers, but it is done as a whole under the organization of Congress and direction of the President.
Then how did we end up with multiple state militias? Coincidence?
"serve in "the militia" (singular), which is a federal organization with the President at its helm."
Only on the very rare occasion when the state militias are federalized. Otherwise, the militia serves under the governor of each state.
"If, as you contend, it was all about "state militias", then Congress would not have been granted the power to organize the aggregate thereof"
One does not preclude the other. Where did you come up with that?
It's in the best interest of the nation that the individual state militias are identical in organization and weaponry. I haven't found anything to suggest that the Founding Fathers intended a federal militia. Maybe you can cite some support for your bizarre theory.