I have ~1500 hours in this game and have been playing since the Alpha so I might be biased but this is pretty much the only game I play anymore with any regularity. Every play through is different, every play style has its own strengths and weaknesses, major events can massively change how the game progresses, and many other factors keep bringing me back.
Paradox is constantly rolling out quality-of-life and game-play updates.
Comparing the game now to what it was just a year, let alone 6, years ago shows just how much love and attention Paradox has for their fans.
Looking forward to another 1500 hours of galactic conquest!