The biggest disaster that went through the entire Japanese side of the videogame industry like wildfire was almost certainly caused by the influence of Western games. Beloved franchises (especially JRPGs and SRPGs) were redesigned from the ground up until many weren’t even the same genre anymore. Just a few examples:
1) Shining Force Shining Force III was not just the best SF entry ever; it was one of the best SRPGs ever made, period, with three interlocking Scenarios where the decisions you made in one determined which characters might be available in the others, With 190 hours of gameplay including EPIC battles late in Scenario 3, from an optional dungeon whose boss could take more than an hour to defeat to the final, multi-stage battle featuring all three of your armies (a possible total of roughly 50 characters) and one of the best storylines ever, it was arguably the Saturn’s finest achievement.
The problem was that Sega completely bungled its release, not even bothering to release Scenarios 2 and 3 in the West (which left Western gamers with an eternally unresolved cliffhanger). Their meddling was so bad that Team Camelot left to form their own studio. Since then Sega has turned the IP into a series of bland, forgettable Action RPGs.
2) Front Mission Square/Enix once had a fascinating and deep near-future SRPG series in Front Mission. Players could build and customize their own squads of huge mechs to go into battle against everything from infantry, tanks, and aircraft to other mechs. The storylines had political intrigue and complexity. Unfortunately with the last entry, Front Mission Evolved, Square/Enix thought it would be a good idea to turn it into a third-person mech shooter. The game bombed, and we haven’t seen this IP since.
3) Final Fantasy/the Tales series/etc. Figuring they could squeeze more money out of what were already profitable RPG franchises by switching their turn and menu-based mechanics out for button-mashing, combo-heavy ones where the player controlled only a single character at a time, Square/Enix, Namco, and others fell into the trap of “Westernizing” those IPs by trying to make them appeal to the more ADD-addled, FPS and fighting game-loving crowd. To some degree it’s worked out for them, but at the cost of much of what made those franchises so beloved for more “old school” players.
4) Valkyria Chronicles Sega tried the same thing they’d done with Shining Force when they made Azure a third-person action title. The game bombed and the blowback from fans was fierce. It’s no small miracle that they actually made Valkyria 4 shortly thereafter; they haven’t done the same for any of their other JRPG/SRPG IPs since.
Let us now pause to remember some of the great JRPG and SRPG franchises that have long since left us, and which will likely reappear in the form of “spiritual successors” made by the original creators (examples: the Shenmue 3 and Eiyuden Chronicle Kickstarters) if we ever see them again:
Panzer Dragoon Saga
Breath of Fire
Phantasy Star (the Algol series)
Final Fantasy Tactics (although Project Triangle Strategy seems to qualify as a “spiritual successor)
Skies of Arcadia