Traveller and the SF games that followed it had the same trope. It was embedded in them. It traced its roots back to Star Trek and Star Wars. Very simply the Universe was flaming huge and you had to paint it in very broad strokes indeed. So we had empires that spanned a galaxy, planets with one biome, and societies where everyone wore the same hat. All the Tlingans were warriors first. That Tlingan chambermaid you hired because I haven't put in rules for robots yet? She could snap your neck and is a qualified sniper. Check my earlier posts: The Only Sci Fi Cliches You'll Ever Need 1-4. I do it too sometimes.
Traveller had its own call outs to this convention. Star systems each had one main world and screw the others. Hexes had a star or nothing (though if you really had a galaxy one parsec thick those hexes would be very crowded indeed; but I digress.)
In working up my ATU I realized I couldn't paint the Icy Shores in broad strokes. It'd take one or two strokes tops. Man just hasn't gotten that far into the Universe yet. Several million people live in extrasolar systems so far but I've assumed that nearly every nation on Earth will be able to participate in this colonization. I don't need aliens if I have people of every stripe (more to come on aliens though.)
Having come to another star system I doubt people are just going to plop down on a garden world and ignore all the other bodies' research potential and minerals. In fact a disproportionate number of colonists will be from asteroids and space station. Those are the kind of people you want when the time lag to the service desk is 4.26 years both ways. They may turn their noses up at blue (or green or yellow) skies, fresh running streams and grassy fields and get right to work mining asteroids and setting up industry in space so the fields stay grassy and the sky stays blue.
Not to mention every planet is going to be pretty shitty to live on from someone's perspective. I'm sure some people are going love the thrill of their type M primary sending them scurrying for shelters when it flares every few hours.
In the Icy Shores I have humans reaching less than twenty light years from Earth and that's using rogue planets as stepping stones for a fuel hungry jump drive. Every light year will have something important: a fueling station, or pirate base or pirate base with a fueling station for a front. A hex might have several stations crewed by all kinds of people (a Moari station, an Ainu station, and a Martian Colonial station!)
I'm going back to my original maps in my post The Icy Shores and Sunless Seas and thinking perhaps the scale is still too big at 1 hex = 1 light year. A light year can hold a lot of stuff.