yeah short of putting a restriction like "BPs upto the highest age reached in that world" or "BPs upto your age" that's going to be a thing. (and it was somewhere between Iron Age and high middle ages that MrBombo who won it would have been in, highest player in the world might have been TE though)
Then again it's not any different from when any new GB is introduced to the game. First of any GB always have a flood of donators looking for BPs. You're right it did have a large impact on that world, but one that at that time would be impossible without spending a lot of diamonds. The alternative would have been to wait until someone reaches future age and buy the goods from them instead of buying through diamonds (or wait until reached Future era)