Oh, there will be people that will buy the book. Sussex fans, since the main character is a thinly veiled Meghan Markle and those, as you say, that buy it to hate on it.
I've watched Scobie in interviews that have been posted here in past threads. To me, he comes across as very off putting. He's very arrogant, entitled, and he speaks to people as if they are beneath his intelligence. Oh gee, who else does that sound like? There was an article in Harper's or Vanity Fair years ago where he bragged about how utterly wealthy he was, maybe so, but that breeds resentment in people. Then there was his Wikipedia entry, almost three pages touting all his accomplishments, which nearly all were false.
He's an individual that wants to be famous and wealthy, but not really put in the work to be really creative as well as talented. Whenever he fails or gets into trouble, it's someone else to blame and he doesn't learn and grow, Just like two other peoples. So yeah, he still hasn't learned and suffers from the consequences.