Well its a matter of which became obvious, rather which pairing became more obvious over others as time went on.
I mean NaruSaku, NaruHina, and SasuSaku all had "the right stuff" to develop into good pairings from a baseline.
NaruSaku as the loser boy loves the girl who loves the talented boy
NaruHina as the shy insecrue girl always liked the outcast boy
SasuSaku as the good girl loves the bad boy.
We got the love chain of Hinata loves Naruto who loves Sakura who loves Sasuke who doesn't give a crap.
But thats just it, as time went on, the validity and chance of each shifted.
SasuSaku took a big detour and delay with Sasuke running off cause Sasuke was a power hunger jerk obsessed with revenge.
NaruSaku and NaruHina however improved over part 1.
NaruHina mainly left off at the end of the chunin exams with Hinata.
Narusaku however soared during the events like her discovering Naruto, not sasuke saved her from Gaara and then of course the promise and her own resolve to help Naruto, heck that scene where she smiles and says "I beg you, I trust you completely." Basically it was a postive outcome for Naruto out of his failure to get Sasuke back, while he didn't succeed with Sasuke, he had managed to succeed with Sakura and even inspired her to do much better for Naruto and herself.
When part 2 began, we could say that NaruSaku and NaruHina were about even, not much had been advanced in NH so it was largely untapped at the time, NaruSaku obviously got some progress over the course of part 1 going from her hating Naruto to being great friends and trusting him.
But that was it, part 2 came up with more naruto and sakura focused stuff. Revealing the 9 tails, discovering the removal of a bijuu causes a jinchuriki to die, learning about the akaskuti, seeing the 4 tails, yamato's input, failing to get sasuke to return, offering to feed naruto after he told her that it felt like they were getting closer to sasuke, the hug, the reveal from sai to sakura, the land of iron events, the hope for the good ending to team 7, sakura's notion to not let naruto handle everything himself, her rally speech at that, etc.
Much NS stuff just kept piling on, in both small casual and larger meaningful moments. NH had plenty of chances and even acceptable times it could have been shown and displayed, but it didn't. Its far past that point now. Since 631 caused such a calamity, with next chapter's inevitable talk no jutsu event from Naruto to Obito, well Naruto has seen Obito's memories including how he loved and lost Rin. Naruto mentions anything love related to Sakura, the event will just again show Naruto still loves her.
NH had many many many chances to develop. In all that time, kishi chose pain and 615 yet neither has advanced that much. NH had a golden era to advance, the time between 469 to 631, kishi could have developed more with Naruto and Hinata if he seriously did want to end NS with the I hate people who lie to themselves line. But in all that time, not once did Naruto respond to Hinata nor show his feelings having changed towards Sakura. Not one moment in the war arc did Naruto and Hinata have enough screentime to advance their relationship, even with the short meeting of him telling her she is stronger than she thinks, it was so minor, again it really didn't go anywhere. NH didn't go much further, the hand holding which many saw as important, it has quickly been smoldered by other events like 631. Not to mention, 631 just made a big connection of Sakura to Kushina, even as minor as it was, shes still the only girl compared to Kushina in anyway shape or form canonically.
As for SS, well the land of iron events and 635 speak for themselves as what is obviously not going to happen.
NS has become more obvious, no doubt about that. All had an equal chance in the beginning but as the story was written, well NS became more prominent.