Trump’s first term shows that nobody except family can last long in his inner circle. Musk’s presence on election night shows that he has currently bought his way into that inner circle. When will they have a falling out? This is somewhat subjective, but I will use things like musk losing any official or unofficial roles in the administration as signifiers. If musk never has any such role, then I will use public reporting of musk visits to the White House or having calls with Trump ceasing for a prolonged period of time.

I seeded the answers with the next several months, feel free to add later months. I will not bet in this market since it is somewhat subjective.