People would give it it's due credit if it had the same effect on them Disney has. But it's just not the same.
Universal can add as many Potter rides as it wants, but it's still just Potter. It's not timeless and people will get bored of it eventually. People are also forgetting that whilst they've added attractions they've taken some classics away. For me, Jaws being shut down for another Harry Potter ride is a huge negative. And if we want to talk stale lets talk about Men In Black.
Universal may cram all it's thrill rides into 2 parks but that doesn't make it a better theme park, not for me anyway. In fact the majority of things that have changed at both Disney and Universal in recent years have disappointed me (Overdoing the Potter stuff (especially in getting rid of Jaws and changing the Dueling Dragons theme), The Avatar Land, updating POTC, Space Mountain and TTA) so new things aren't always good. I'd rather they kept the things I loved about the park before, whether that's the employees, the attractions, the music, the scenery, or whatever.
But nah, these currently popular fads don't really do it for me. I mean, does anybody in their 20s even know who Doctor Sseus is? Kids in 10 years won't.
For me, Disney just does what Universal does better. And I include MGM in that.