I remember as a kid, we would go to the Reds games. And they had the all-star ballots. Te punch card ballots.
We would grab a bunch of them, start punching all the Reds players. And if one was not on the ballot, they had a "write-in" vote.
Now this was the time of The Big Red Machine. So EVERY Reds player deserved to be on the All-Star team, the starters anyway.
I think one year 7 starters did make it, in the starting line-up or close to in. Some pitcher was the starter, maybe from St. Louis, and can't remember the other position. May have been the SS from the dodgers, as Dave Concepcion was the other SS behind him.
Fans voting counted back then, the NFL I guess they still rely more on coaches and players votes.