Universal's growing crowds are 75% due to Wizarding World. Yes, people are now visiting for Volcano Bay too, but take a look at the 2 most recent rides to open up at Universal Resort - Kong and Jimmy Fallon. They are both screen based rides and not ones i'd consider as thrill rides per-se. And Fast and Furious is going to be a screen based ride too.
Yes, a lot of the popular rides at WDW are thrill rides, but you are forgetting about some of the tamer rides such as Haunted Mansion, Peter Pan, Toy Story Mania, Frozen Ever After... They are all great rides which usually have a long wait and yet they are not thrill rides.
Wizarding world is pretty old at this point. Whats important to note is that crowds are GROWING at Universal, and they are SHRINKING at WDW. Its not a matter of both growing and one just doing a bit better, though even that would suggest one was doing a better job of satisfying the market. WDW attendance is down, Universal is up, considerably.
The non-thrill rides you point to fill up for a couple reason, 1 - the big thrill rides are already full 2 - the cater to the demographic that CAN"T ride other things. I mean, I love me some toy story and haunted mansion, but the most popular rides at WDW remain the thrill rides, there is simply no contesting that.