How would ensuring the IRS is able to correctly do its job make more money for the ultra wealthy?

Their system is a hodge podge of bailing wire and duct tape strapped cobal. I don't think there's a way to "fix" it other than redoing it in pieces.

Because Elon giving the finger to the public is more important

He literally gloated on his website about closing it

that would benefit the people and not a large US company.