Militias don't have to fight directly against tanks and fighter jets. That's why they're effective.
You can't maintain a police state by blowing up houses. If you do that, you end up cutting off your only revenue source (taxing employed people), because your tax base either can't or won't work (because they're dead, the roads are impassable, etc.). In fact, this situation would actually be quite beneficial to an insurgency, because if an attacker can't pay or feed their foot soldiers, they will lose their army.
In the end, you need foot soldiers to maintain a police state. It's not economically feasible to give everyone state of the art sniper rifles like this, and spending 10x more money on soldiers doesn't make them 10x more effective.
It is exponentially harder to maintain a police state than to destroy one, which is why even poorly trained, poorly equipped insurgencies can effectively fight against well trained, well equipped governments. If the US government has problems with this in Vietnam and Iraq, imagine how much worse it would be if they tried the same thing on their own well-armed revenue source.