My guess, and it is purely that, is that without the second world war you buy a generation, without the first world war you might see it last into the 21st century. Recall that the last pockets were kept up until the 1970s, even later if you consider Southwest Africa, and you had a revolutionary USSR, anti-colonial super power America, the fall of France, the fading of the British and the destruction of Germany, Japan and all manner of reordering of the world inside of fifty years. Give it at least a better polish of stewardship and development, and it plausibly could be rather long lived.