KSP1 took 5 years of development to get to 1.0, at a non-software company.
Take-Two then bought the game in 2017 and is responsible for ports and KSP2.
So while KSP1 likely generated returns of Squad-magnitude with a few resources... that doesn't mean KSP2 is capable of generating Take-Two-magnitude returns from a full team.
Dwarf Fortress sold a lot of copies too (finally), but it's also been in development for 21 years!