It's not everyone who ever picked up a headset. Sometimes a wrestler would call a match out of nowhere.
It's also not just announcers who started the show; I've gone through phases (probably mistakes) where I'd have announcers call shows in waves.
It's some type of combination of all of that.
Here's the list of WWF PPV announcers. I told you there was content. We're about to hit the ten year anniversary. Wait until the content after Mania. Content!
Jim Ross 65
Joey Styles 36
Gorilla Monsoon 29
Jim Cornette 23
Taz 22
Jesse Ventura 14
Paul Heyman 13
Matt Striker 11
Jerry Lawler 8
Josh Mathews 8
Steve Regal 7
Bobby Heenan 7
Roddy Piper 6
GHB 5
Mick Foley 4
Christian 2
Tony Schiavone 2
Michael PS Hayes 2
Tommy Dreamer 2
Scott Stanford 1
Michael Cole 1
Dean Malenko 1
HHH-M 1
Undertaker 1
Bret Hart 1
Vince McMahon 1
Skip McMahon 1
Al Snow 1
Lord Alfred Hayes 1