Actually there’s a way to get mew in the original game without attending one of the events, although it relied on the missingno bug. Also you had to be aware of it very early in the game, and skip facing a particular trainer until much later. But yeah you should totally have just got it when you got all 150.
And it was impossible to catch mew.
I’ve always had a little hatred for Game Freak because of that.
Actually there’s a way to get mew in the original game without attending one of the events, although it relied on the missingno bug. Also you had to be aware of it very early in the game, and skip facing a particular trainer until much later. But yeah you should totally have just got it when you got all 150.
I’m aware of the bug and have confirmed it works on original hardware but it wasn’t intended by Gamefreak so they’re still pricks.
Completely reasonable position to hold, have a great day