You might as well be asking what color is the sky during the day. Yes, they are vital to the big 3 because people buy consoles to play games and exclusives make each of the big 3 distinctive from each other. Nintendo only has it's exclusives to rely on. So right there, the idea that exclusives aren't needed is beaten. To further add to it...
Both the PS4 and xbox one have 3rd party support. Most of their software sales come from 3rd party games but what gets a person choose one console brand over the other?
That thread asking what reasons do people have to buy a xbox one. The main two answers were exclusives and halo. So what would happen if the xbox one didn't have it's exclusives?
Playstation consoles are as popular as they are thanks to exclusives. People took interest in their games and they couldn't play 'em anywhere else.
