When American empire was made the age of capitalism was in full swing.
At least try to sound objective.
A 'capitalist paradise' was made out there.
But anyway, history cannot be used to extrapolate the future in such a way. We have so much now they didn't back then and if the time comes for spaceward expansion they too will have a lot more then we do.
History cannot be used to extrapolate the future, but we can examine historical cases and see what occurs within certain margins (in this case: small number of people with a huge number of comparative resources). It's called a case study.
This is especially useful for looking at human behavior because people tend to obey a sort of quantum law: we can (and often will) act differently when we know we're under observation.
C: Children are annoying as hell.
They're a full time job and really not to everyone's taste.
And B still applies here, people will still have careers and big hobbies that take up the bulk of their life.
I've got a few cousins who were raised while both parents had full-time jobs.
The fallacy you're committing with your assumption is you're extending a contemporary trend into infinite. You must look at
causes, not just derivatives.
People are shrewd (no matter how much you seem to believe otherwise), they will do what is most beneficial. Everything, in essence, is a value judgment. When it is economical to have only a few children, they will do so. in the modern West, for instance, children are expensive and parents often have careers they don't want interrupted. They decide to limit the amount of children they have.
However, in older times the more children you had the more workers you had for your farm. Modern poor in America sometimes have more kids because welfare pays out for a larger family.
Now, hypothetical post-scarcity (because post-scarcity really
is pretty much impossible) society. People do not need to worry about virtually any material need. You don't need to work a job, you don't need money to have a house and food, why not have a child? You may feel you don't have the time for a baby, but this is a transient feeling. What about later on when you do feel you have time?
Why, exactly, would the population decrease?
Well I'm an optimist, I tend to hope we will get a utopia rather then this distopia of trillions (even 1 trillion in the solar system is horrificly crowded)
Are you kidding? A trillion would have more than enough space in the solar system. The asteroid belt alone contains more than enough in the way of building materials to house a trillion with extreme comfort, along with the necessary support infrastructure to keep people alive.
The solar system doesn't start getting all too crowded until you start talking a lot more. There are a billion asteroids in-system larger than 100 meters. That's a ridiculous number. You could easily house thousands in each, too.
The actual causes of the trend are not due to a lack of money at all. The poorer people actually tend to be the ones that have more kids.
As education and opportunity increases birth rates fall. In such a scenario as the optimum future educational and other opportunities will be virtually limitless.
And they also spend a whole lot less on their kids and, as I pointed out earlier, they gain an advantage by having a lot of kids.
Seriously, think about a future where someone has a kid, lets him/her grow up, then has another. It's really one kid at a time, and average life-spans will probably extend into the triple digits within the century, let alone the far future.
And for the record- Any idea of fixing earth's population troubles with space colonization is a bit silly, a 'scant few millions' is really a best case scenario for people we can initially get out there. The rest will have to be made on site.
What?
When fully developed our solar system will no doubt house dozens of trillions. We have so much space we would literally spend decades or centuries figuring out what to do with it.
Yep, I've heard of that. A thread on that where the initial discussion against me on this thread comes from.
I've never read the books but from all I can gather the Cultureverse seems to be exactly the kind of thing I am proposing here.
Well then, I'm sorry to tell you but the Culture includes a lot of physically impossible stuff to make its situation possible (hence the sci-fi thing). The Grid (their well of infinite energy), field technology (generic manipulatable force fields), superpower AIs the size of a truck, and a few other things which are essentially fantasy technology.
Effective post-scarcity situations
can arise, but it's still finite resources and it usually has to be planned (ie. it's not actual post-scarcity, it's just one is put into a specially designed set of margins in which one cannot experience scarcity, but there are still limits). It's certainly not going to happen just because we start developing the solar system.