While the exact speed of hyperdrive is still debate most mega-nerds agree that it'll take you across the galaxy in days at most https://movies.stackexchange.com/questions/65883/how-fast-can-hyperdrive-equipped-star-wars-vessels-travel. Given this why are the outer-rim worlds still so intensely impoverished backwaters complete with scum and villainy? It would be like claiming that San-fransico is simply too far away from Washington to govern effectively since it would take ages to reach it by car or train. I mean Greece is not a frontier land to the British by any stretch of the imagination so why should Endor be to Coruscant.

This problem gets even worse when you consider that star-wars has instantaneous messaging across any distance.

I am of course aware that the "real reason" its that George Lucas wanted to use backwater-worlds as they'd be cheap enough for filming and then hyper-drive's fast speed was set, so I am looking for an in-universe explanation (presumably from legends as I doubt there is one in canon).