"can you train your dog to ACTUALLY protect you adequately?"

Of course, but training a dog capable of protecting you is not a skill everyone has. Before he died, my last GSD would:
1) Step to the side of the trail, and "down" if a bike or jogger approached. Would thus notify me if I hadn't seen the person approaching... and would stay respectfully out of the way until told o.k.
2) Would attack, seriously, on command or without command (if I were struck, went down, and said nothing further). Would cease instantly on command.
3) Would "bluff" on verbal command or hand signal: he would stare at you, bark and slobber, and LOOKED like he wanted to eat you... but this was not an attack command.
4) Would carry his own food and water in a saddle bag on hikes.
5) Would "find some sticks" drag fire wood into camp all night if I let him.
6) Would track (found a lost child once, in a campgrounds) on command.
7) Would point a squirrel, retrieve a duck from the water, or follow a blood trail.

So YEP. I wish he were still with me. A better woods companion than any human I ever go out with.