In the end, SE is only using the PS3 as an excuse to NOT advance the game. The easiest solution is to drop PS3 support once and for all. However, the problem here is that PS4 sales were sub-par in Japan and SE could potentially lose quite a chunk of the community they actually care about.

Also, as stated at the beginning, it is a convenient excuse to not do changes. They feel that they are in a comfortable place so they try to remain there as much as possible. This won't change unless the JP community complains about this.The west is just an additional market that can be milked (see CE prices being 1:1 translations).