There just aren't competing colonial or imperial powers anymore. WWII and the agreements between the western powers directly afterwards set the stage for one imperialist power and many vassals. While non-US western countries certainly have their neocolonies and partipate in empire, they have no means with which to stand on their own as imperialist powers.

I think we are already starting to see what a multipolar world looks like: cross border cooperation to improve everyone's material conditions.