Comment by Imnimo

There is an interesting old article by Magic's creator about what the game environment was like during the early playtesting days - when card packs were handed out to a community of playtesters at UPenn, and they traded in a closed ecosystem, occasionally getting an influx of additional cards. It seems like this was a pretty successful recreation of that feeling:

https://magic.wizards.com/en/news/making-magic/creation-magi...