American's believe airplanes will hit each other or the ground if they don't follow routes (Victor airways) and receive a separation service.
Victor Airways are just "advisory routes" really. A VFR pilot can bash around them, through them, in them whenever they like too.
If you file a V aw then as long as you are at the MEA then you will guarantee navaid reception and terrain clearance. However there is nothing to stop you filing GPS DCT - I once was flying back to an airport in Socal which had some convoluted routing along airways so I just asked for a DCT routing via GPS at about 12000. As the aircraft equipment was /G meaning IFR approved GPS onboard then I got it. 300mn DCT.
The difference in the USA is that all IFR is controlled and therefore requires a clearance. I actually think this is a good thing.....