- Starships were being built on the ground prior to the Kelvin Incident, as seen in the Linlithgow Shipyards.
They do it in the 24th century too - we get a glimpse of a Galaxy-class ship being built on the surface of Mars in TNG: "Parallels" (although I must admit... that wasn't the prime universe!)
Also the Enterprise's saucer was refitted on the ground in San Francisco in one of the Lost Years novels.
- Just how many years was Scotty on that ice planet?!?
He says six months in the movie.