The real reality is that themes are themes. Some are great, some suck. And a half baked original theme is going to pale next to a great license. Just like a great licensed game is better than a mediocre original one, unless you buy games to just look at them.
In a perfect world you'd get a great game with a great theme, that was wholly original. And it's certainly possible. But it's just a ton of work. Take it from someone working with a license right now (Alien with Fox) it's not like working with a license is necessarily easy. You have to stick with the rules that come with it. But at the same time, you have this whole universe to play in. You're not sitting there for weeks sketching and trying to design cool looking bad guys, the xenomorphs are right there. Everyone knows them. When the beacons on the top of the game go off you're going to be remembering scenes from the films, there's extra memories and emotions triggered there.
It's tough to beat that now.
I just moved my Mystic inside the house, it's in my home office right next to me. Beautiful game, I love it. But if you made a modern title with the same art you'd have to have so much more. Callouts. Characters. Animations. Tons more music and sounds. We have a lot of expectations now. And that all has to be created from scratch. There's no license to give you assets, ideas, and frameworks.
If you're Stern, and you're paying for your employees' time, and you have to keep the line moving, you simply can't take a year off to noodle around with creating that stuff. They're on the clock, and under pressure to make every game count. A missed license (WWE) hurts, but an original game that gets ignored is probably way more painful.