The "eggs in one basket" is only one among many and I used that one to just cover reason I thought could help people to understand the importance of expansion into space. Nothing makes people understand teh gravity of a situation better than the threat of extinction ;) hehe

Also, I completely agree with the questions your have posed. As a race, we never really "needed" to do anything. We could have just lived like our ancestors in the stone age and just kept living normal lives, doing things like hunting, gathering, reproducing. But that's not who we are. We are an explorer species and it is in our nature to head into the unknown. 

I am glad people like you exist on the planet and understand the reason to the question "why". The world would have been totally different otherwise. Cheers man!! :) :)