"How does anyone know that the brakes need service"
Not a car guy, eh? Here's a hint: that terrible screeching sound you are hearing every time you hit the breaks means you need to get new pads, IF you haven't already destroyed the rotors.
Sounds like you are not the car guy. The screech you hear can be chatter from the brake pads, or from the wear indicator. It is NOT and indication that you need to replace the brakes, it is an indication that you need to inspect the brakes. Brand new brakes can cause a screeching sound if they do not have the proper shims installed, or an anti-screech compound put onto the back of the pads.
There is nothing to cause a screeching sound that would also destroy the rotors - neither brake chatter nor the wear indicator will cause damage to the rotor. If you hear a grinding noise, then the brake pad has been worn completely away (at least in one place, or on one side of the rotor). Of course someone can hear steel on steel grinding. You can feel it in the car when the brakes are applied.
As for rear drum breaks, they are only an assist. If they go out, it just makes the front breaks wear faster.
Anyone who understands physics understands that the rear brakes do not provide as much stopping power as the front, regardless of whether they are drum or disc. However, up to 40% of your stopping power can come from the rear brakes. If you're driving without rear brakes, you had better hope you never need to make a panic stop. In a brief Googling the best I could find for you is the Motorcycle Safety Foundation's Basic Handbook that indicates that the average motorcycle has 30% of its total available braking power in the rear wheel. It does not say that the rear wheels provide nothing but brake assist, that is just absurd. And I would prefer to NOT ride in the car of someone who only has 70% of their total stopping power available to them.
I support the rights of the people, including their right to free enterprise without interference from men with guns, whether they be banditos or g-men.
You're right, people deserve freedom. However, being a member of society requires that you follow certain norms. For simplicity's sake, why don't we call these norms regulations? These regulations forbid you from murdering me, for instance. The general purpose of these regulations are to prevent injury or harm to others. If you'd like to go back to the days without any sort of government regulations, why don't we just go ahead and let you, your partner, your parents, your children, nieces, nephews, grandchildren, or any progeny of your family work in a factory for 100+ hours a week?