When Isaac Asimov wrote about space travel he'd send out the best and the smartest. His universe is full of lightly colonized planets with some of the best educated humans and tons of robots1. Most of Earth's brightest have been lost to the stars while the poor, the uneducated, and miserable are stuck on the home world. That leaves a planet crowded with the people most likely to have more kids while those least likely to have a bunch of kids are out on empty planets. Earth has few robots because the humans need the work. Despite having more people, the people on Earth are pretty much stuck since the brain drain has allowed all the people who could develop advanced weapons and fighters to live elsewhere.
OK, that was a bit more than needed for my original point. The so-called best and brightest are on the ships. Space travel is expensive so they want the best trained to get the most for their money.
Heinlein was in the Navy until some lung condition forced him out. He views starships more like Navy vessels. They're crewed largely with people you're more likely to find in a bar than in a lab. Crude, loud mouthed, and handy with a wrench. The planets have people who are indentured servants. People you're likely to see working the fields or the mines on modern Earth. Hopefully when you've finished your contract you have enough money left to pay your way home or else you have to sign on for another contract.
Gene Roddenbury's universe (Star Trek and Next Generation) was more like Asimov's not because only the smartest got to move away but because he made everyone the smartest. The education system worked, the government was benign, and they'd achieved the perfect balance of capitalism and socialism to see that everyone had the chance to be something great.
I'm not sure what my point is other than to notice that difference between these different visions of the future.
What's your vision?
1Discounting the Foundation series.