The Trump children are dreaming if they truly believe they would have the positions they have if not for their last name. Neither Ivanka nor Jared has qualifications anywhere close to what is needed to be a presidential advisor of any kind. And Eric and Donald Jr. wouldn’t be running a business empire if not for their dad (and don’t forget, Donald Sr. got his start through his dad).
At least when JFK appointed RFK to be Attorney General, the latter had some law qualifications for the job. But that created such a stir that it served as the catalyst for the nepotism laws that followed.
Just one nitpicky point. You say, “Ivanka thinks it’s fine if the taxpayers who pay her salary…” — and Ivanka isn’t getting a salary. However, I bet she gets a staff or at least an assistant (in addition to her West Wing office), and the taxpayers no doubt pay for those.