I wonder how those hours are tracked... If it's through Origin, it's worth noting that it doesn't track any of the hours played in Offline Mode, even if you go back Online later. I imagine most are playing in Online Mode, but like others I started playing offline a while back for stability reasons (so it's missing ~100 hours I've been playing offline).
It won't track people that opt out of telemetry either. It's a lower bound number.
You know how many people didn't even beat Ostagar in Origins? It's a fairly high percentage.
I was just curious and did a peek at Skyrim's steam achievements. I think the prologue is "Unbound?" 14% of people don't have that achievement. 23% didn't get an achievement for level 5.
I don't know the data for our game but undoubtedly there's people that haven't played very far for reasons that are their own. They may not have liked it. They may have gotten busy. Something else came along and stole their attention away. It's pretty common, for better or worse.
As for dragons, I think I only killed 4 of them myself. We have to be careful of self-selecting data from our peers and those we interact with since they may not be representative. It's also important to remain open to other interpretations (i.e. people that love the game but don't care for dragon fights, or RP that they don't want to kill them, etc.).