I've got 212 hrs on Stellaris, and I only downloaded it at the beginning of December! I've definitely never racked up that many hours on a game that quickly. By comparison, I've played Team Fortress 2 on and off since it came out like what 10 years ago? I've played that for what I thought was a long time, and I'm only at 283hrs.
My downloading Stellaris just happened to coincide with my wrapping up a project, so I've had an abundance of time. That said, it does kind of remind me of Civ 4 back when I used to play that, and you would constantly say to yourself "just one more turn".
Stellaris doesn't have turns, but it's the same kind of feeling. "I'll just keep playing until the Cruiser tech is done researching". Hours later you're still playing.
The game has a loooong learning curve... there are so many little nuances and quirks that you only really find out the hard way. My complaint about the game is that the pop-up tips and info when you mouse over stuff can be sorely lacking in the type of clear data you're looking for. And unlike Civ, I find that the online wiki's and forums searches often produce out of date information or none at all. I remember the CivFanatics forum what a damn goldmine, with spreadsheets and everything. Stellaris, from what I've found, simply lacks a good tutorial... but then for a tutorial to be "good" it would be like 8 hours long to tell you what you need to know. So really you just have to start playing and expect that the first several games you will just abandon because you'll see how you've messed up and want to start over. Even now I haven't ever "finished" a game... I just get tired of that particular empire (and I can see how the rest of the game is likely to play out) and I start a new one.