This doesn't really hold up to scrutiny if you're a serious Star Wars nerd, I would suggest. It's certainly not true re: "spanning millennia".
The problematic bit is "rebels fighting from within a corrupt and inefficient democratic bureaucracy", which isn't a major theme in Star Wars at all (quite the contrary), and is so entirely vague as potentially cover everything from a senator disagreeing with a policy to actual rebel insurgents running a terrorist campaign against a genuinely oppressive government.
It's also not true in the current post-Disney EU.
In the post-Disney EU, most eras simply don't have any detail, so you definitely couldn't call it either way as to whether either of the two situations was occurring (though again, the second one is so broad it's arguably always going on in all democratic societies - like I could argue it was true at literally all points of US history post-Revolutionary War, though I wouldn't want to because some of the people you'd have to argue for are pretty gross!). Even in the pre-Disney EU, most of the 4000 years between the Old Republic (where neither condition was meaningfully true, note!) and the Battle of Yavin was just a blank slate and we couldn't say either way. Indeed it would be safest to assume neither was happening, logically.
In the new, post-Disney EU, we only have significant detail on one period outside that of the decades around the Battle of Yavin, and that is the High Republic period, which is like 100 years before that. And in that period we definitely don't have either an evil empire, or a corrupt bureaucracy. The High Republic bureaucracy is somewhat inefficient and slow to react, but that's because it's democratic in a more genuine way that a lot of Western countries, especially the US, and is governing much of an entire galaxy. But it isn't meaningfully or significantly corrupt - and they actually make a point of this in the High Republic books. Rather the big challenge it faces is simply trying to govern such a vast super-nation full of diverse peoples. It actively tries to avoid being oppressive, which doesn't make that easier. And when I say slow to react, they do manage deploy stuff to save people within hours of a threat, more than once, and actually cause pretty huge problems for their adversaries (mostly a vast pirate fleet, which is definitely not fascist/imperial, rather more like an evil version of anarcho-syndicalism), but they're not great at anticipating threats and getting ahead of problems (partly due to overreliance on the Jedi, I would suggest).