Well, considering it took us thousands to hundreds of thousands of years (depending on whether you buy that certain, more chronologically recent adaptations played a significant role) to start developing the rudiments of technological civilization, after evolving all the biological assets of intelligence that we have now,
The end of the last glacial period might have had something to do with it.
The end of the last glacial period might have had something to do with it.
Still thousands of years even if we suppose the window was closed before then.