I think Trump paid Hurwitz surreptitiously to write this speech and no one can admit to it. She can’t cop to moonlighting when she works for Michelle Obama. You cannot plagiarize yourself but you can repeat phrases that you successfully used before.
Trump likes to hire the best. Who is more experienced than Sarah Hurwitz at first lady speechwriting? The entire speech is written in her style.
Trump got his wife the best speechwriter he could find so she could look good. But dumbass Hurwitz got lazy or assumed those were common themes that no one would notice.