In the 80s and 90s, third party exclusives were a necessity because you were making games for sets of hardware that were capable of dramatically different things.
They were capable of dramatically different things. Perhaps they also had those contracts, but Genesis couldn't do mode 7, and the sounds that came out of the SNES were dramatically different. There were cases where a game would come out on each system under the same name but developed by two different companies with two completely different designs, because their capabilities were so different.
In the 80s and 90s, third party exclusives were a necessity because you were making games for sets of hardware that were capable of dramatically different things.
No no they were not and in addition to that nintendo had contracts that outright forbade developers from working on other systems period.
They were capable of dramatically different things. Perhaps they also had those contracts, but Genesis couldn't do mode 7, and the sounds that came out of the SNES were dramatically different. There were cases where a game would come out on each system under the same name but developed by two different companies with two completely different designs, because their capabilities were so different.