The truth about Taiora
There is no doubt Sora and Tai are really good friends. We can probably say there is something more, at least from Tai's side. How he reacted in certain episodes when Sora was kidnapped when she thought no one loves her ... shows us there must be something more he feels for Sora. Of course there are some parts when Sora's actions for Tai make us think. But it's hard to say if they are made from love or just great friendship. What destroys our doubts in Sora's attraction to Tai is then the second Digimon movie.
But then something unusual happens. In episode 38 we discover Sora likes another one. And who is that? Matt Ishida (Yamato), who she almost never talked to in season 1. Who she rarely talked to in season 2. I don't know when Matt came to Sora's life. It was certainly not in the first season so it must have happened in those three years between the seasons. That's from Sora's side of the Taiora story. Even Tai didn't notice any attraction between his best friends. In episode 38 he finally asks her out but she rejects him because of Matt. So we see Tai still likes Sora.
25 years later all Taiora hopes are destroyed. We see all DigiDestined with their children. It's not exactly told Sora and Matt are married but ... Even a blind person would see how similar Sora's child and Matt are and Matt's child and Sora are. Sora's child has blond hair and Matt's haircut and Matt's child is like small Sora.
So what happened? These are just my opinions. I think that Sora was interested in Tai at some point but he didn't see it and he missed his opportunity. When watching the first two seasons I was always wondering how Matt and Sora could end up together, since there were no hints for that ending. But after watching the Tri series (I know, it's not really from the same time and setting) we can see a little bit more about their relationship and it doesn't feel like it's out of nowhere like it does if you watch just the first two seasons. I'm pretty sure that when Kari came into the series Tai's concern for Kari became bigger than for Sora's. He was always just thinking about Kari, Kari, Kari so there is no surprise Sora could feel deserted and alone by Tai's side.
We also know that the head writer Satoru Nishizono didn't like Taiora and saw the two of them just as good friends and planned Sorato already from the beginning. Then why so many Taiora hints if she would end up with Matt anyway? The second movie didn't have anything to do with Satoru Nishizono and most of the producers, writers liked Taiora more, so that's why there are hints everywhere.
Anyway even if Sorato was planned from the beginning it's still very surprising to me and a lot of other people. I always saw him more with Mimi since they are both artistic persons and Sora and Tai are more into sports. Opposites attract apparently. ;)