I like putting thought into the reasons why a setting must work a certain way. It’s good practice for a roleplaying game, where some player will ask "hey, can we do X?" and I need to have a better reason to say “no” than "it will wreck my plot".

So if you want to keep a Star Wars game running the way you think it ought, but don’t just want to stomp on a player’s ideas, try the following ideas.

I joined the Jedi Order at a young age. I received training in the Force at the Jedi temple on Coruscant. I constructed my first lightsaber using kyber crystals I found myself on Ilum. And I learned why the Jedi are instructed not to form attachments.

An uncountably long time ago, the founding races of the Republic had independently discovered “Element Zero”, or “eezo”. Eezo is a unique form of matter capable of creating what was once called the “mass effect”, which facilitated interstellar travel, antigravity, and other wonders. Living beings whose nervous systems had traces of eezo developed unusual capabilities. Those beings who traveled into space met other lifeforms, some similar, some not. Together they created an interstellar government called the Republic. And for a thousand generations, it stood as the torch of civilization across the entire galaxy.