Kidd will make a comeback and play an important role as ally in the upcoming war.
His defeat against Shanks was just Oda's way of making it clear that he's out of the Pirate King race, which is now in its final stages (same with Law).
How can you miss the extreme similar build up?
Luffy looses the first time completely, his whole crew on SA. -> Kid looses the first time completely, his whole crew on Elbaf.
Against a worldwide feared Warlord which sold himself to the government -> Against a worldwide feared emperor which sold himself to the government
Looses the most important person for him at that point, his brother -> Looses the most important person for him in the past, Victoria Punk, a ship memorial for his first love
Gets saved under water (by law) -> gets saved from under water
trainings arc with the dark king (Rayleigh) -> gets trainings arc (off screen) with the fallen king of Elbaf, Loki.
Fake Strawhats appear -> fake kid pirates appear
real ones appear with massive boost -> *coming soon*
There will also follow even more, like Luffys red hawk in resembles in Ace. Kid will use the scraps of the Victoria Punk as armor and call it Punk Victoria (like all his abilities are called).
Kid is not out of the race, he is just starting to run.