Those 8 great civilizations were way more advanced and not all were human. It is not even known if our current civilization got to be one of those 8 or not. Maybe we got conquered by one of the aliens that made one of those 8 civilizations :)
One of those 8 also fixed the Sun so it didn't lose its heat and light.

Current humans were left to their own devices so they did what they could. Mining mostly was not needed since they could use advanced materials found everywhere.
Even gold and gems have no worth in 9th world due to so much access to advanced materials that are then used for currency (since people don't know how to replicate and create it, only mold it into other stuff; kind of like Valyrian steel in game of thrones).

I've played about three hours of the beta now but it's sadly not quite my cup of tea. I guess I should have done more research on the setting before pledging but too late now :) .
It is definitely more interactive novel than game. You can easily spend several minutes in the double digit range at every single named NPC before all dialog options are exhausted.

Since I'm not familiar with the setting, I actually read all the descriptions and texts. After those three hours I'm still on the first map of Sagus Cliffs (a city that consists of several maps). I've been to some of the other maps to solve a quest but it was only a straight back and forth affair to get that one quest done.
In fact, I have only solved a single quest in Sagus Cliffs in three hours(!)

So, this will be a dream game for those of you who like it extremely slow paced and text-heavy with as little flow to the gameplay as humanly possible. It will also help a lot if you have the time for long play sessions since you would barely make any progress in a half hour to an hour play session.
If you prefer to make tangible progress in a game and like it when a game has a certain flow to it then I'd advise to look elsewhere. It's a playable book. Maybe even a really good one and fans of the setting will certainly love it but it's MUCH (much, much, much…) harder to get into than PS:T for a regular gamer like myself.

the end.

Thanks for the run down, Moriendor. That is what I was afraid of. I still backed it though, just because it was in a special "two-fer" deal, along with Wasteland 2.

Oh well, I suppose I could just imitate many of the young gamers of today and click through the - what seems like endless dialogues - without reading them, lol, to try to speed things up a bit, but we will see.

I was little afraid about the same thing. But they do/did revisions of all texts. So hopefully they will shorten or "streamline" :) some stuff.