Why would a soulmate be some random person close to your age? For them to be your soulmate, you’d have to have some things in common, surely? That’d make it much more likely that you’d meet them.
Close to your age was a given of the What-If to avoid the possibility that you either would never meet because you lived in different eras, or underage minors getting involved with much older adults. As for what makes a soulmate, I presume it’s a combination of personality and (perhaps literally) chemistry, which probably would transcend things like language or culture.
Another song on this theme: Ana Ng by They Might Be Giants.
I don’t think personality would transcend language and culture - we’re a product of our environment, after all. How could someone be your soulmate if you never ever laughed at the same things, for example?
Sure, but he was using it as an average. Personally I go days at a time without ever looking a stranger in the eye. I might see as many as 10 on a busy day. So 50,000 in a lifetime? Highly unlikely.
Because soulmate transcends everything. Didn’t you see the Colin Firth section of 2003 documentary, Love Actually?