The purpose of the state militias was not primarily to defend the states against the tyranny of the Federal government. The purpose of the state militias was to defend the state and the nation as a whole against foreign invasions, to fight hostile Indians, and to crush riots, revolts, and revolutions against the state governments, as well as to protect the states against the tyranny of the federal government.
As a result of the reliance on the militias of the states and territories, the army of the federal government, the regular army or the United states Army, was kept small during the the 18th and 19th centuries. Too small to effectively police the frontier between settlers and the various Indian tribes and to keep people, white and red, safe from the brutal violence of frontier warfare.
But the state militias tended to lose their military effectiveness almost from the beginning of the US constitution. Though every citizen was supposed to keep a rifle and ammunition ready and to report for periodic drilling, the militia laws were usually unenforced and in, for example, the War of 1812, most of the militia that was mustered was badly lead, often unequipped, and untrained, and was not of much military use.
And for most of the 19th century the militia remained somewhat better than no militia at all, but in most cases of rather limited military value.
To add to the small regular army and the small militia forces available, the US government raised temporary troops during the Northwest Indian War, the United States levies. In St. Clair's disastrous defeat in 1791, the highest ranking officer killed was Richard Butler, major general of United States Levies.
In the War of 1812, The Mexican-American War, the Civil War, and the Spanish-American War, units of volunteers were raised. States and territories would recruit volunteers, organize them into units up to regimental size, and commission the officers (who were often elected by the soldiers of their units).
The units would then be mustered into Federal service, and the officers and men would be paid, equipped, and supplied by the federal government. Thus in accounts of Civil War battles most of the regiments have state designations, like the 69th New York Infantry, for example.
At the turn of the 19th century the modern system of National Guard developed, with voluntary membership instead of the universal membership theoretically decreed by the old militia laws, and with joint federal and state control.
Did the southern states regret the decline of the militia system when the Civil War came along and wish they had kept strong militias to protect them from federal tyranny? Maybe.
But there were only 16,000 men in the United States Army in 1861. In December 1863 the Rebel forces reached their peak strength of 464,646 men while the federal forces reached their peak strength of 1,000,516 in May 1865, almost of the men both armies being in temporary volunteer forces.
Thus the size and the effectiveness of the state militias and of the United States Army was of little importance compared to the vast armies of volunteers raised and equipped by both sides.
And the memory of the death and destruction and suffering of the Civil War has probably kept almost all later Americans from considering resorting to armed force to try to oppose any tyrannical actions by local, state or federal governments, and they have usually preferred to oppose tyranny with peaceful protests, politics, and appeals to the courts. The fear of another widespread Civil War is enough to keep most Americans from resorting to armed uprisings to oppose perceived government tyranny.
Thus the original purpose of the 2nd Amendment has become unfulfilled, due to the 19th century failure to maintain effective state and territorial militias and the reluctance to start another terrible Civil War.