Spiderman is a licensed property. Marvel sold time-limited video game licenses. The Activision games were never exclusive to any console because Activision had no particular stake in any one console. Then a video game license, a non-exclusive one, mind you (which means that other people can get the license and make games) was granted to Sony, who obviously does.
Thus, for the same reason 007 Goldeneye never came to playstation, Insomniac's Spiderman games aren't coming to Nintendo or Xbox.
but spider-man used to not be exclusive
Spiderman is a licensed property. Marvel sold time-limited video game licenses. The Activision games were never exclusive to any console because Activision had no particular stake in any one console. Then a video game license, a non-exclusive one, mind you (which means that other people can get the license and make games) was granted to Sony, who obviously does.
Thus, for the same reason 007 Goldeneye never came to playstation, Insomniac's Spiderman games aren't coming to Nintendo or Xbox.