These are related. If Earth had higher gravity, acceleration to get into orbit would need to correspondingly be more violent. A 2g Super Earth, while possibly a fantastic super-habitable target for advanced space-faring us, is likely not a Fermi Paradox problem because of how difficult using early chemical rockets on it would be.
Point about this issue: a 2 G super-Earth is probably about as massive as a planet can get without being an ice giant. Approximately, mass scales by radius^3 and surface gravity resembles radius (this is because mass scales with volume which scales by radius^3, and surface gravity scales with mass divided by surface area, and surface area scales with radius^2). Mars has about 1/8 of Earth's mass, half of Earth's radius, a little less than 1/3 of Earth's surface area, and more than 1/3 of Earth's surface gravity. Luna has about 1.2% of Earth's mass, almost 1/3 of Earth's radius, 7.4% of Earth's surface area, and a bit less than 1/5 Earth's gravity.
If it has the same density as Earth, a 2 G Earthissimo would be 8 Earth masses, which is a really big superterrestrial planet and IIRC pretty close to the line where it would be big enough to hold onto molecular hydrogen and probably become a ice/gas giant. This is probably a fairly extreme world and much more massive than most terrestrial planets.
According to
this escape velocity calculator, a planet with 8 Earth masses and twice Earth's radius would have a first cosmic velocity (minimum velocity to put something in orbit) of 15.82 km/s and an escape velocity of 22.37 km/s. By comparison, Earth has a first cosmic velocity of 7.9 km/s and an escape velocity of 11.2 km/s. A planet with "just" 4 Earth masses and 1.6 Earth diameters gets you a first cosmic velocity of 12.5 km/s and an escape velocity of 17.7 km/s.
Or maybe all civilizations eventually discover a trick to break physics for infinite resources & they leave the material universe alone as a nature preserve to grow new civilizations.
One possible partial Fermi Paradox explanation I've considered for my own science fiction is the same branch of physics that allows hyperspace travel in that setting might also eventually allow access to "layers" of the universe that are more habitable for a highly advanced civilization on the level of Orion's Arm Archai (though not necessarily more habitable for primitive flesh and blood beings like us), and really advanced civilizations tend to move to these "super-habitable layers" and abandon our "layer." Like, you know the
aestivation hypothesis? Maybe there's a layer that's already got a CMB temperature of some tiny fraction of 1 K, so they can move there and skip the billions of years of waiting. Alternately, there might be a layer that's much denser and more energy-rich than our layer, if highly advanced civilizations prefer those conditions. Heck, both might exist and really advanced civilizations might live in the cold layer while "mining" the hot layer for energy and matter, getting the best of both worlds. One of the setting conceits is "fast" interstellar travel is possible by taking a short-cut through a sort of "basement" of our universe that kind of resembles our "level" of the universe maybe a few tens of million years after the Big Bang when it was in a much more compact state and has a correspondence between locations in the "basement" and locations in our space. A ship can go into the "basement," travel maybe a few hundred AU, go back into the "living room" level, and be in the Alpha Centauri system. This "basement" is fairly useless for anything but a short-cut; I'm thinking its environment kind of resembles a
giant molecular cloud but with a "warm" cosmic microwave background temperature of maybe around 50 K (still deeply cold by human standards; Uranus upper atmosphere temperatures) and made of almost pure hydrogen and helium (like our "layer" of the universe before the first stars). But if this "basement" exists, maybe there's other "levels," including "attics" that are sort of like the way our "level" might look in the deep future black hole era and other "basements" that are more energy-rich. The idea I have is the universe is sort of an "onion" with many of these "layers," the "basement" we're familiar with is just the one that's energetically "closest" to our "living room" layer and therefore the only one accessible to relative primitives like us (or maybe one of the only ones; there might be a deeper "basement" that's too energetically "far away" for ships to go to but is used by humans for interstellar communication).
Of course, this is psuedoscientific fantasy, but not really more so than FTL.
