it isn’t like the quality of the games themselves nosedived

I would argue it has. the early games were very story-driven and well written. the latest few, if they’ve continued the trend from Odyssey, which is the last one I played, are bloated, repetitive, boring, the writing is terrible, and the story is almost impossible to follow because you can play for several hours between consecutive plot points, and sometimes have to because of level-gating