Personally I attribute it to being a pretty cool and mysterious phrase to drop right into a story, attributed to a character that was truthful, but exceedingly cryptic as an individual whom was trying to impress a sense of duty on an impressionable young man, hoping one day he would kill a pair of sith lords. 1000 generations is cool, yeah, awesome. Qui-Gon would be proud of that one.
The answer is Yes; the Republic is pretty old and so is the Jedi. Kinda in the same vain as "Making the Kessel run in 14 parsecs" or something. It's just some jargon that the characters drop that mightn't be necessarily precise; but the characters in the universe know what is meant because they live in that universe (Though whether Obi-Wan thought Han was impressive or just full of Tarntarn is another question. It's a lukewarm argument.). Lucas basically was world building and adding and dropping details as he went on like a GM would so I wouldn't take any of the concrete statements of star wars all that seriously as characters, like people will embellish things frequently to their benefit which from a certain point of view, might be right. It's how Lando makes a living after all; that guy just ends up faking it until he makes it. But needless to say, I wouldn't necessary take characters at what they say as a concrete answer. Embellishment is a key trait of humanising literature and chances are facts are pretty fluid in even the most serious of media. XD
As for breaking laws, yeah. The Trade Union committed some serious war crimes with potential for genocide in the blockade of Naboo, fast forward some years later and the same vice-roy is still in charge despite being arrested, blood on his hands in the Naboo Throne room and forced to surrender. I kinda get the feeling that "breaking laws" and "accountability" relies on individuals in the republic being interested in holding the represented accountable. We don't know much about the laws of the land but I get the impression that the Republic never really took the battle of Naboo all that seriously; it was a conflict that took place somewhere far away and they probably slapped a fine on the trade union for overstepping their mark. Kinda astounding really how a figure could do those kind of things yet it doesn't seem to threaten the end of that guy's political career like it would in our world. It was only when a gigantic uprising came about and the Jedi tried to assassinate the supreme chal in his office did the republic really become invested in anything beyond their own backyard politics.
I guess the bigger the galaxy, the smaller the problems seem to be until it happens right on their doorstep.
Edited by LordBritish