The difference between a military and a militia is training. Yes, tanks and big guns are extremely easy to fire, but do you know how to work together with others to use those weapons to launch a coordinated assault? Have you practiced and trained until you can work with your squad to clear a building without thinking about it?
This is what has fundamentally changed in the American military since Vietnam, we have fully changed from a loose organization of mostly short-term enlistees, draftees, and officers to a core of professional soldiers who will spend 20+ years in the service, and you know what, it works like a sonofabitch. It raises even the average private in the US army to a level 10, 100 times higher than the members of your militia because they can work together as a team. One on one your militia of hunters and private citizens might do alright, but you don't get any bonus from having them together. If I take a bunch of guys from a military unit the whole is going to be much more effective than if they fought individually.
Training is expensive and time consuming - your militia will never have the time or the money to train the way a regular army can.