You don't have to convince me Trump is greedy, but he can easily make an absolute killing without Musk as well. We are about to see corruption on a whole new level in Trump's second term. But it's Trump that holds the keys here.
Trump has the thinnest skin in the world. Any media story about Musk running things behind the scenes or exploiting Trump, could get to him. But I do agree that Musk is sleazy, and probably clever enough to avoid pissing him off directly.
There is simply no comparison. Trump has the full power of the executive branch, as well as the absolute loyalty of the majority in both houses of congress. He is also the one supported by the people. Musk has a social media site. I will maintain that Musk has already done about 98% of what Trump actually needed him for, which was helping him get elected.
Whether they fall out or not is pure speculation. I don't see it as a certainty, but definitely a probability. And if they do, it probably won't be a public spat, but will be spun like Musk having done his work making government perfect, and therefore going back to run his companies. But it's clear to me, that this is not some 50/50 partnership that is mutually beneficial for the two. This is Musk latching on to Trump's teat and sucking as much as he will allow.