Have you ever read one? Even the genre's exemplars are disposable vehicles for self-promotion.
In some cases the advances amount to outright influence-peddling, granted with no expectation that anyone will ever purchase enough copies to justify the expense in terms of sales.
In other cases, politicians buy thousands of copies of their own books to gin up attention. Sometimes they are distributed to supporters; in other cases, they sit in a warehouse until they are pulped. Incidentally, this is also a good way of converting campaign contributions into personal wealth.
Just step in to your nearest thrift store and count the obviously untouched copies of Decision Points or The Audacity of Hope on the shelves. These books are written - usually poorly, and by someone who spends minimal time with the politician - for the moment. They're not meant to have relevance for more than a couple of years.
You pretty much pre-empted my own planned post about these books being more often than not thinly veiled pay-to-play, plus the Pryor posters note about them being set up just to do a book tour and seem like a very serious individual. However, I will nitpick about your including The Audacity Of Hope in this category. That was one political Memoir that belongs in the other exception to the rule category that was actually quite well written, overwhelmingly if not entirely written by its actual purported author, and was done as a vehicle for Obama's presidential run rather than some naked cash grab. Again, there are exceptions to the rule oh, do you are generally right here.
