I know this is a bit silly to treat the Star Wars galaxy so seriously but I look at the universe from a Watsonian point of view as opposed to Doylist.
So. I was reading the Timeline of Galactic History page on Wookieepedia. In Canon these events happened.
Before 25,000 BBY
Various species develop a hyperdrive
The Galactic Republic is formed
1000 BBY The Republic reforms after major wars with various factions and then the Sith
200 BBY High Republic era. Noticeable difference between the society from then till the Prequels. Beings are just starting to explore the Outer Rim
32 BBY The Prequel Era. The galaxy is settled
0 ABY Original Trilogy era
34 ABY Sequel era
Now aliens invented the hyperdrive before 25,000 and had it for 24,000 years. The Republic reformed. Then High Republic. Then the movies.
There are major changes in technological development over the course of the 3 movie trilogies which is only about 60 years.
What is a plausible explanation for why there was so much change in tech and science in 6 decades in the galaxy but the civilization remained static for 24ish centuries after developing FTL travel?