I fully support PokeShipping but even I don't pretend that it was ever "canon." A canon ship would mean that two characters would be in a confirmed romantic relationship with each other and May and Drew never were. They didn't date, they didn't kiss, they didn't do anything that couples would do, not even by anime standards. Back to the point about Serena; as I said before, I really doubt that writers are capable of juggling her goal and her relationship with Ash. If they were capable, Serena would've had a goal from the beginning that she would work on while also having a desire to be with Ash, and yet only the latter has happened. She has a huge crush on him but doesn't seem to care about Rhyhorn Racing anymore, which was her only real hobby when she was introduced.If you want another example, look at Pokeshipping: Ash X Misty was the definite subplot of the Orange Islands arc. Point being is that the writers are more than capable of having Serena juggle her feelings while giving her a main goal.