the prevalence of firearm ownership in the US is itself a function (likely an intended one, by the framers) of 2A.
No, it was 100% intentional. All able bodied men below a certain age were legally obligated to muster with their local militia, and they were likewise legally obligated to provide their own firearm. The gov’t had already granted itself the right to raise and equip an army, so the idea that 2A applies to the gov’t being allowed to arm itself is patently ridiculous. No, the idea was that individuals would own firearms, and would undertake some form of training (or regulation) in their use, and that would make them fit for militia duty.
From that perspective, it’s clear that the founders intended the people to have access to and own weapons fit for military service.
I agree that it’s unlikely that the people should need arms to resist the gov’t, buuuuuuuuuuut it’s happened, and it’s happened in recent memory. The Bundy clan had an armed standoff with the gov’t in the 2010s over their illegal grazing on BLM land, and the gov’t ended up being the ones to blink first. (Also, the Bundy’s won in court over that; the gov’t did some pretty egregiously illegal things, and te judge tossed the whole case out with prejudice.) You can also go back to standoffs and insurrections by Native Americans in the 70s, standoffs that the Native Americans ultimately won. Moreover, we have a strong current of fascism running through our current politics; IMO, the idea of willingly giving up arms when the fascism supporters control the House, and have overrun the judiciary is madness.