To be fair, in Book 4 onwards, Voldemort was back and wanted to kill him. Nobody wants to be killed by an all powerful psycho.

Eh not every fantasy series needs Lord of the Rings level of depth. At the very least, this did make HP very accessible at a younger age. I grew up when the books were first coming out so I aged with the characters (I was 17 when Deathly Hallows came out) and was able to make some easy connections with them and felt like the stories were "growing up" with me.

I mean just saying, if I craved "story depth" from everything then I'd probably hate something like Mario games (they're as shallow as you can get, story wise, but they more than make up for it on the basis of just being pure fun).