I think neglect of the battle system is why the genre is now more or less going extinct. Most people just can’t take grinding through dungeons for 30 hours anymore.
I think its bigger than JRPGs.
By and large more powerful technology has removed many of the abstractions we used to have in games. Back in the day it was challenging to land a jump in Tomb Raider because Lara was stuck on a grid and the low visual fidelity made it hard to gauge if you could make a jump or not. These abstractions made the act of jumping and exploring in itself a challenge. Now we have games where you can hold down a button and cling to the world in lightning fast real time.
JRPGs are going through the same thing, things aren’t abstracted through menus anymore, why use a menu when you can swap weapons and spells on the fly? And just mash X to win like in Kingdom Hearts/Crisis Core?
Abstractions are probably the most meaningful component of a video game that most forget about, or even complain about. They may seem artificial but I feel they are vital in setting up the thematic/mechanical beats that get a player involved and invested.
The proliferation of large game worlds is problematic too, a lot of open world titles where traversal is a boring chore. How many games give us this large field to run around in and then make us resort to using the dodge roll to get through the screen quickest? (NIER)
When we had pre-rendered backgrounds and little space for data, game directors had to be picky and convey the most atmosphere with the smallest space.
For example, all the love it gets, I always found that MGS3 failed to bring the sense of precise, deliberate design that MGS1 and 2 had by taking place in a nondescript and open jungle area.