Except that anime deliberately separated Goh from Ash just before his final match with Leon. It's a lesson to real life that sometimes, you will miss the most important event of your friend's life. And Goh's situation is much worse because unlike the other friends, who are watching Ash live on TV, Goh is on a helicopter pondering in his thoughts. He couldn't even witness the grand finale because it would conflict with his dream.
When looking at Ash's friends during Ash vs Leon, they're all in locations that visually showcase their career. Misty is at her Cerulean Gym, Brock is being a doctor, Serena and May are performing a contest, etc. They're all in pursuit of their dreams, and only a few (like Dawn) can make it to the actual tournament in person.
Really, the thing that was missing was a grand celebration party of Ash's victory in Kanto. That is where you call in everyone for one final party. Where everyone can put aside their dreams for now to celebrate the dream achievement of one Ash Ketchum. But that's another story.
As I've stated before, what matters isn't how many times Serena and Ash meet post-XY. Rather, it's all about the context within the meetings they have that matter the most because that's where casual audience can get a better understanding of the unique relationship between Ash and Serena.