This is your experience and if UOR doesn't appeal to you the same way Disney does, that is totally valid. For me, as an older Millennial female who grew up with Disney IP, I still highly preferred Universal until I had my son in 2020. So USF does not mainly cater to boys/men and I feel the nostalgia factor applies particularly to people who grew up visiting DL in California or grew up in, or with family in, Florida and were able to go to Disney parks periodically growing up. My first time stepping into a Disney park was when I was 22 and as much as I love Disney IP, at the time MK was "ok". I didn't go back until 2019 when I was 33, on an adults only trip, and I had a great time but we did both UOR and WDW on that trip and I far preferred UOR. I guess I just prefer thrill rides. Your wife is obviously much different in this regard but I know men (my brother comes to mind) who do not like coasters either so both of us are anecdotal here at best.
Now I have a kid and thus I've recently become a Disney adult, I guess. My now 3 year old has been to
Disneyland once (first time for my husband and me) and Disney World twice with three more trips planned this year. My appreciation for Disney parks has increased exponentially almost entirely through seeing it anew through my son. That said, we are going to take him to Universal when he is almost 4 in September. He will be able to ride around 75% of rides (if he makes it to 42" which will be close! If not he will be able to ride over 60% of attractions). He will also love the dragon in Diagon Alley, Animal Actors on Location, Seuss land, all things Minion...in this case though we are able to tack on 1-2 days and get everything done so I see how it isn't really taking away from Disney. We are doing it in ADDITION to a week at WDW.
When Epic Universe opens it will absolutely take away market share from Disney. Not for those who, like I said, grew up visiting primarily Disney parks. But a lot of visitors will be able to easily spend a week at UOR between the three theme parks and the highly themed water park which is generally considered the best water park in Florida and really a theme park in its own right. I for one cannot wait to take my little one to Universal but Epic Universe will be a game changer with Isle of Berk Dragons, Nintendo World, etc. Families with limited time on a once in a lifetime trip might do just 4-5 days at Disney where in the past they'd have done a whole week or ten days, and spend 4 or 5 days at UOR as well.
There is plenty to be nostalgic about at Universal and even more so with Epic Universe opening. Harry Potter came out when I, a 37 almost 38 year old, was 11. Minions is awesome, I was hooked on The Mummy as a youth...Universal has their own Marvel area that is awesome...I definitely think millennials and younger generations are not going to be as devoted to Disney as generations past. HP world is so well done and Epic Universe seems to be following this same approach. My generation and younger are going to go wherever they can get the better overall experience.