So Africa separated from Eurasia in 1869? And if canals count then Northern Germany is its own continent, Great Britain is several continents, etc. Man-made canals forming a meaningful geographical separation is a weird concept on so many levels
Obviously, but in case the sarcasm of my comment didn't come through: I was trying to make the point that you can't draw lines between continents just because of geography (or tectonic plates for that matter). It's arbitrary - after all we can't even agree which continents do exist.
It's an interesting topic since most people in a hypothetical Eurasia would probably never call themselves Eurasian, but would have a strong sense of being one or the other. But on the other hand there is also no universally agreed to boundary between the two as well. And maybe this imprecision the best representation of reality that we have for this.