Closed circuit vs low resistance resistor
The old saying that "electricity follows the lowest resistance path" or whatever the case may be, is misleading. In true fact, parallel resistances form a current divider with each "leg" of the circuit carrying a current inversely proportional to the resistance. So, while a lower value resistance will carry more current than it's higher resistance neighbor, both will still carry some current. In the case of ideal circuit analysis, wires (and switches) have zero resistance. By evaluating the current divider formula as a resistance approaches zero, you can see that that leg will conduct a share of current that approaches 100%. 

In summary, you are correct that in the real world, nothing is ideal and zero resistance is impossible. This means that some tiny current will be flowing through the 600 ohm and 1 ohm resistors, with the majority of it flowing through the closed switch. However, the current in the resistors is going to be so small it doesn't matter in practically any circuit.