Get ready for another analytic megapost, because I have a hypothesis!
TVTropes, on one of its presumably lesser-visited pages, talks about the difference between what they call
"Watsonian" and "Doylist" explanations. To put it briefly, a Watsonian explanation is an explanation within the fictional universe, while a Doylist explanation is one that explains why something happened in the media from the perspective of outside forces that affect the creation of the work itself.
To put this in amourshipping terms, the Watsonian explanation for why Serena has a crush on Ash is... well, we all know the story from camp, and how Serena would later grow up to lack motivation to pursue individual goals thoroughly while Ash does, so she admires his determination, etc.
What might be a Doylist, or outside-of-canon explanation? Well, that's what I'm hypothesizing about!
If we assume that the writers are considering their domestic market first and foremost when writing the show, I believe it to be a reasonable suggestion that Serena's existence in the anime, her crush on Ash, and her hypothetical eventual relationship with him are, from the perspective of the creation of the show itself, at least in part the result of
Japan's population crisis, which first rose to public attention
at least as early as 2013.
For those who are wondering what the "population crisis" is and don't feel like reading the above link (or the other material I will link in this post), Japan's population is decreasing, and is beginning to skew more towards the elderly.
The cause? A low marriage rate. An
extremely low percentage of children are born out of wedlock, and even the number of children per couple is comparatively low. This means that there are simply fewer young people to pay for the social programs of the elderly, and fewer people in the workforce, especially since those women who
do marry generally proceed to then drop out of the workforce due to societal pressures. What's more, with their relatively unwelcoming attitude towards immigrants, they can't, as of the current cultural state of the country, bring people in from outside to pick up the slack.
So indeed, the primary cause of the low birthrate is a low marriage rate: far fewer young people are settling down and having children. What is the cause of this cause? The most frequent (and, in my opinion, most reasonable) explanation is
the hundreds of thousands, if not one million Japanese citizens on the younger end of the population who have shut themselves in. This rather significant portion of the population has allowed their lives to be so completely consumed by dating sims, video games, anime, and the Internet that they get
absolutely no physical face-to-face interaction outside of their own parents, which naturally means bad things down the line in terms of prospects of marrying and having kids.
Because of this, efforts are being made to, as
this headline puts it, "encourage[] young people to date and mate."
I hypothesize, based on all of this information, that Pokémon might be trying to do its part to encourage precisely that: the writers presumably know full well that their show is probably watched by children who might be at risk of growing up to be that sort of "shut-in" and/or by young adults who already are. They also would obviously be well-aware of just how popular their show is, especially in Japan. Thus, romantically pairing up a character who has been, and will continue to be, a role model to a lot of kids might encourage those kids to think about the possibility of finding a romantic partner for themselves, which is something that Japan really needs for its economic health. The fact that Serena is from the Pokémon equivalent of France could either be a happy accident or an additional deliberate and subtle decision along these same lines, since, as I mentioned above, it would also benefit Japan to be more welcoming towards foreigners, in part because immigrants will probably be needed to help overcome the workforce shortage that will be caused by the decreasing population.
So there you have it: a possible explanation as to why Amourshipping has a significant chance of going canon, from a real-world perspective!