The "problem" for developers is the same that other enterteiment industries have , on you reach the top of the growing curve you need tons of money to get the costumers attention since there are hundreds of options around.
Marketing budgets must be huge compared to 80,90s games. AAA games also have more risks so developers don't move from thier core IPs and new ideas are discarted.
Finally since games are about fun 500.millions budget does not guarantee you success if your Game has Bad gameplay, lore, writting, etc...You can easily be surpassed by a fun indie Game like Balatro.