>>17422463The problem is that main means singular, primary, the one, the main reason you're here.
Wrestlemania might have 2 nights, there's no denying the fact that there are 2 shows with an 81 hour intermission, but that doesn't mean there are 2 main events.
Last year there was only 1 reason to see Wrestlemania: Cody's story.
This year there's only 1 reason to see Wrestlemania: Cody versus Cena.
Yes we have the match with Punk, Roman and Rollins. It's slapped together right in time for the show. Is it the primary event though? Not over the whole 2 nights.
The first night is secondary to the second night.
Psychologically, the first night is the bottom card leading to the second night's mid and upper cards. You can credit decades of sports programming with that.