Circuit Analysis and Voltage
You clearly have to differentiate between schematic and real circuits. In a schematic you, most of the times, just represent the actual components you have in your circuit. In your example this would be your 3 resistors.
As you already stated, the wires between these components are ideal, this means they have 0 resistance and therefore 0 loss. As a consequence, node A and node B of your ideal schematic have the same potential so there's no potential difference.
When you switch to reality, of course there are no ideal wires, this means every wire that carries a current will automatically suffer from a voltage drop so when you build up this circuit, node A and B will not have exactly the same potential - for most cases this is negligible.
Wires and they're parasitic characteristics start to play a role at very high frequencies or high currents where you either have to keep your voltage drop in mind or control the effects of loop inductance at high current transients.
But to start, when analysing a schematic as yours, wires are ideal and therefore have no voltage drop.