I think "levelling the playing field" is a very dangerous assumption. You're not levelling the playing field - the person you are thinking about fighting is a criminal. He will have much less restraint in using force than you will, so he'll be at a massive advantage. On top of that, given that robbing people might be his full time occupation, he'll try to be armed better than you are, so you don't put up resistance (he has no interest in being killed or killing you, after all).

So essentially you're triggering an arms race, the results of which can be seen in the US.

The European (or possible "every other developed country") approach is to not even try to fight criminals (again, you have little chance anyway, they are professionals after all) but rely on the police, where the police has such overwhelming force that no reasonable person would try to fight them.

Given crime statistics, the European approach appears to result in a lot less crime and violence.