memes

Also there have been eras in earths history where it was basically like one of two environments. Like before the continents emerged from the oceans properly, or the several snowball earths, or the multiple times a super continent formed and created swamp land and desert land because of the fucken Appalachian mountains.

Water doesn't have to be the thing that brings variation. Titan has a methane "hydrology" with clouds, rivers, valleys, and beaches whose sand is made of ice. On Triton, ammonia cryovulcanism powered by tidal forces from Neptune create plains with ammonnia snowfall, ice mountain ranges, and underground lakes. On Miranda, the planet is ice, but there are massive terrain differences from 10 km cliffs to flatlands. Io has a massive variety of volcanic planes with color differences visible from space because of their entirely different chemical compositions. The turbulent atmosphere of Jupiter is streaks of water vapor clouds, upwellings from deep beneath the surface, cyclones and massive pressure drops that dent the atmosphere inward by kilometers, with ionosphere above and gas as dense as water below. Even an atmosphere-less grey rock like Mercury has basalt plains, craters, ridges, highlands and dust plains.

In No Man's Sky, many planets have life, which requires complex chemistry being possible at the temperatures the planet has using the chemicals that are available on that planet. This then naturally creates temperatures that are "too cold" for that life and "too warm" for that life, and complex adaptations made by that life to take resources from places that get "too cold" or "too warm" with less risk of predation or competition. Similar adaptation is possible to other extremes/variations, such as "submerged", "on land", "flying", "too dry", "too few nutrients", "too acidic", "too basic", "too steep", "cave", etc. And thus we get complex biospheres that vary across the planet.

My guess is that a rocky planet that is 5% - 95% covered with ocean is probably pretty rare. You probably mostly either get water / ice planets or rock planets.

Another thing that makes Earth unique is the liquid iron core. Without that you don't get a magnetic field. Without a magnetic field, it's hard to keep the atmosphere intact. That means that water vapour gets blown off over time, which eventually results on a dry planet like Mars.

As for all 3 states of water, as long as you're in the range to have a wet surface, you'll probably get all 3 states of water. The poles will get a lot less solar radiation than the equator, so if the equator is wet it's pretty likely that you'll get at least a bit of ice at the poles. If there's a lot of water then it's easy to get water vapour. Even Europa which has an average surface temperature of -171C (102K) has a liquid water ocean under the icy surface, and although its atmosphere is extremely thin, part of it is water vapour.

Personally, I think you're half-right in that (with a sample size of our solar system) the Earth is the only one with an actually diverse range of biomes - really only possible because the availability of water in multiple forms...

But the Earth-like planets in NMS should rightfully have the same biome diversity if they were being scientifically accurate...

Though we all know the real reason for the lack of diversity is to force movement between planets. If every resource was on one planet, there's be no reason for the player to explore.

Monobiomes are probably the rule and Earth-like continental planetoids with diverse topology are probably exceedingly rare in the universe.