As a third party publisher for Starfinder who has released a good number of rules supplements - I create crunch for what's missing in the game and what fits my publication goals. I'm not trying to overly burden gamers with rules, but like I created rules to allow starships and planetary fortifications to fight each other, whereas in Starfinder ships are limited to attacking other ships only, and I needed a work-around. I published a crunch heavy guide for Starfinder called Starships, Stations and Salvage Guide, which came out 3 years before Paizo created the Starship Operations Manual, and includes a lot of the same stuff (similar rules and same in some cases), but I have 5 times the options that Paizo provided. For that I needed more things for starships to be able to do - cloaking shields, grappler arms, be able to become submersible or vehicle once a starship lands, ramming rules, boarding rules, salvage rules, etc. I create crunch to fill the holes in the game, is all. And I mentioned in a couple other threads, that my recent The Planet Builder - rules to create scientifically viable entire star systems, and their stat block for homebrew setting development. While those rules were designed for Starfinder, they're generic enough to be usable in Stars Without Numbers, Traveller RPG, any sci-fi game system - since many sci-fi games lack that facility.