You know, I think you’re right. How many times have you consumed a piece of media and said “you know, this was /ok/, but what it really needed was a convoluted love story”.
No, typically the inclusion of a romantic plot is seen as a detractor from something that could have been good rather than something to be added to a mediocre bit in order to make it appealing. And the most common complaint? The writing, or how a relationship is handled. Most usually hat it felt forced. It seems that just as in real life, romance is not something that can just be decided upon. It needs to grow organically, given time to breathe.
As an in universe example, I won’t deny that the Gwen/Kevin romance was absolute trash when they first started out and tried to force it. Once the writers got started and stopped feeling like they had to try and “make it work”, their interactions felt more natural, and I found the ship growing on me.
Likewise, Ben and Kai were forced together. They had little to no chemistry in any of their episodes together, and what banter they shared felt unnatural. Compare to the friendly banter between Ben and literally anybody else. Is it any surprise that the fans prefer to ship Ben with Gwen, or Kevin, or Rook over Kai?