Many thanks for doing this analysis. I've always been interested in game theory and the modern vintage metagame is a great case study!

I actually think it's entirely possible that vintage is a 'one deck format'. There are many ,many reasons for this, here are just a few off the top of my head:

We can't assume that everyone has perfect information. With the advent of MODO vintage and analyses like this one, we are trending towards more information, but it is far from perfect. Some players still show up with outdated decks. And I'd argue most don't know the 'win percentage' of archetype A vs. Archetype B.

We can't assume everyone is a rational player, whose sole goal is to win. People have deck and play style preferences that push them towards sub-optimal strategies. Some play to have fun, so winning is secondary.

Another hypothesis is it is much easier to 'screw up' playing blue than shops, i.e. blue decks have a larger decision tree and therefore also more opportunities to make mistakes. Given that most vintage players are fairly casual and are not on the pro tour/grand prix/scg tour grind, they are more likely to make mistakes when on a blue deck.

I don't know if there's a solution to this problem outside of more restrictions. The power of shops since printing of lock pieces started in Mirridon has always been that even if you packed a metric ton of hate, you still lose if you can't cast any of them. That problem still exists and will continue to exist as long as there are turn 1 spheres powered out by workshops. We know workshops are not going anywhere, so that leaves thorn or sphere, both of which seem way to underpowered to be restricted.

P.S. Frank Karsten wrote an excellent article examining what makes a good constructed format using game theory, highly recommend everyone to read!: https://www.channelfireball.com/articles/what-can-game-theory-tell-us-will-make-a-good-constructed-format/

**last edited by hankzhong**