There are billion of Terrans living on colonies all over GTA space.
No there aren't. According to the FS Ref bible, subspace was discovered only a few years before the T-V war. In FS2, Capella was described as "densely populated", despite only having 250 million civilians, less than the population of the USA. The majority of humanity is probably still stuck in the Sol system.
And yes,
millions of casualties -- no matter how large the total population -- will have a significant political and psychological impact.
I allways figured human culture would move towards simplicity... and it's quite simple today..mostly..
So I see nothing wrong with the future human culture being very similar to what we have today..
It is far from simple today. "Simple" is a nomadic hunter-gatherer society. Human culture today is quite complex. Look at all the laws and regulations on the books, for example.
And if you think human culture in 400 years is going to be very similar to what we have today, then I highly recommend that you drop what you're doing and brush up on your history. Or go read a book, as Petrarch says.
Do you really see us getting devided into castes or some other ****z like that? After we experienced "democracy"?
I hadn't considered castes, but you're probably right about that. Certainly American culture is proceeding towards increasing class division, which is just the modern day equivalent of castes.
And democracy is not a silver bullet. When the morons outnumber the intelligent and every moron can vote, and when electronic voting machines have no paper trail, the system is ripe --
rotten, even -- for abuse.