A question was asked a number of times on this forum, mostly in 2011-2013, of the theoretical reasons for exactly 3 generations of elementary particles. The answers mentioned that certain observed processes could not happen with less than 3 generations, but at that time almost all sources (except this) agreed that the specific reasons for exactly 3 generations were unknown.
My question is if there have been any theoretical developments lately suggesting a theoretical reason fo the number of generations being exactly 3.
The question is about potential recent developments, please do not mark it as a "duplicate" of questions asked years ago.