>>718768880
It's similar to the fimmaking dilemma. Soviets noticed that only 14 or 150 movies made that year were successful. The next year they therefore produced only 14, but this time none were successful.
As budget needs grew, Sony started investing all their money in fewer games that were supposed to be a sure hit, disregarding lots of IPs they didn't deem good enough or worth the effort. But there's no such thing as a sure hit, and now it takes a few failures to completely miss their profit goals. To add to that, the userbase of those other forgotten IPs has abandoned them and wouldn't easily come back unless their changed their policy for at least 4 or 5 years.
Lack of exclusives exacerbates this trend. Result: total Nintendo domination.