I think it was clear from the very first moment when he said that for the very first time that he was not being serious about literally building a wall. That was a figure of speech, and everybody knew it was.
Dude, it is *literally* part of his program right now.
https://www.donaldjtrump.com/policies/immigration/
Of course, I realize it's Trump, so that doesn't mean squat, but nevertheless, there it is, the "figure of speech", down in black and white, first in his 10-point "plan", with a pdf attached on how he will make Mexico pay for it. :P