The problem with this is that there's a very steep drop in probability between 'European countries loses most colonies' and 'European countries loses all colonies'. The latter is an absolute term, which requires all territories outside of Europe to separate. The problem with that is that the overseas territories held by the former colonial powers today are either too weak to stay independent, surrounded by very nasty neighbours with a vested interest in claiming themselves some free real estate, or just too closely tied to the metropole. Most of them, of course, are all of the above, and these territories generally and overwhelmingly lack the will to separate. Just take New Caledonia, for example, which still possesses a marginal chance of seceding from France and surviving. When given the vote on independence last November, it still got a pretty comfortable 'no' vote, though not as overwhelming as expected. Overall, almost all the colonies that wanted decolonization got it (plus a couple or so that didn't), and those that didn't are just too small to survive, or has a firm foot down from the metropole to complain.