If a beta-amyloid therapy eventually makes it to successful trials, there will still be people who believe the argument is already over and the therapy cannot work. The problem identified by Lowe and others is that some amyloid-oriented researchers were not only falsifying data but also acting as reviewers and editors of journals and tanking alternative explanations.
That has stopped, presumably, but alternative approaches haven't had much success yet either.
Therapies targeting amyloid deposits has been tested extensively in actual humans, and it indeed removes amyloid deposits. The main problem is that none of the therapies in question usefully treat Alzheimer’s disease.
Sure, maybe an eventual useful Alzheimer’s therapy will remove amyloid deposits, and maybe it won’t, but it needs to actually treat or at least meaningfully slow the actual disease.