I wouldn't say they're dying, every year we're still seeing quality AAA games that move a ton of copies. But I do think they're facing an existential crisis and are becoming unsustainable.
Development times and budgets of AAA games have skyrocketed over the last 5-10 years, but the total console market hasn't really grown over the last few generations and prices, while higher, have not risen nearly as much. At the same time, people have ever growing backlogs and see fewer and fewer reasons to buy games day one (games releasing in poor state, game pass existing, the expectation of fast discounts, etc), which only makes things worse. I don't really see how much longer it can go on. A high profile AAA flop is catastrophic for all but the biggest publishers, and even those can't take too many of them.
Basically, AAA games only make sense if they're guaranteed to be a hit, and that's not exactly a comforting thought.