The militia is the people, and the people have the right to protect themselves from anything. That includes a tyrannical government. How do tyrannical governments get into power? By meeting little to no resistance. How do you put up a resistance? By using guns.
How do you launch a coup? By using guns..... Sorry, little triviality there.
I think the definition of a militia - an organized, regulated force to 'protect' the people and overthrow the government - is still an important concept with regards to the 2nd amendment. Albeit the people could do very little nowadays against a government with the current US govs' resources, plus my reading is that the militia was created - whilst with a steadily watered-down capacity to usurp the president - with a mind to defending the nascent US from external invasion by the Great Powers and from internal strife with indigenous peoples.
You're right in some cases. However, none of the 1792, 1862, or 1903 Acts hold supremacy--the Constitution and its Amendments do. Call it fear-mongering by the NRA if you will, but Americans like their guns, and most of them interpret the Second Amendment in the same way that I just have.
With regards to the militia, it's hardly been disbanded at all; the National Guard is now the "official militia" of the US. There are dozens of more private militias that fulfill a similar role.
Regardless, surely if you want to interpret the constitution you need to decipher the meanings & context of the words within? How many americans, yourself notwithstanding, are taught about the various militia acts et al in school?
I'm well aware the national guard exists as the current militia; you'll have to forgive me for not being au-fait with the official legality of private militias (who could just as well be Koresh-esque nutters in a camp in the woods, surely?). However, I'm pretty sure the concept of a self-armed, fully conscriptable male militia doesn't exist in US society as it did at the definition of the 1792 act and thus - I'd expect - in the minds of those drafting the 2nd amendment.
To be honest, I'm not all that interested in arguing the 2nd amendments' interpretation; I'm neither a judge nor American after all. But I just think there is still an argument, regardless of common interpretations, to be made for an alternate interpretation.