Can you imagine an alternate reality where we have a singular gaming hardware, and games are all on that one system? This is the future that some people clamor for.
I agree that there may be better ways to spend money that is paid to get this exclusive content, like making more exclusive titles. Guess what, that is a far harder venture than simply buying some timed exclusivity for what is an established title. A company wants to get more sales, and anything that accomplishes that, especially a strategy with a proven track record is one to be adhered to.
I have been gaming for close to three decades, and having to choose one system over another has been a thing that entire time. I have gone through the Nintendo cartridge age where they exercised their dominance, I have been through the Sony PS1/PS2 generations where they kept content from other platforms for some time, I have been through the 360 generation where Microsoft launched early and then started buying timed exclusive DLC. I have seen Sony do it to the biggest titles this generation and more than any player out there. It works, it is not changing.
As a consumer, you get to choose what platform it is you want to game on, this is not being taken away from you.