Under this analysis, what was the short term motive? How does that pay off?

Ingratiating himself with Trump, I imagine. It certainly paid off in the short term, since he was given a golden ticket to sack the government.

A lot of tech execs successfully brown-nosed Trump, which (unfortunately) is understandable to some extent given what was at stake with his tariffs and other assorted threats. But Musk is the only one who evidently enjoyed it.