From @Jaco's article:
To put it more simply, in the current state of Vintage the small incremental advantages you gain by having 4-9 cards in your main deck that are only relevant against blue decks, and blanks against Workshop decks, are often outweighed by the fact that you are such an underdog against Workshop decks that they often don’t even sideboard anything against you in post-sideboard games.
It amazes how often this argument keeps popping up. Why does the Workshop deck not have anything to SB in against the Blue decks? It's because the deck is trying to beat the same metagame that the Blue pilots are trying to beat. Shops players are building their main decks to beat Blue. Why should Blue pilots build their decks differently than Shops pilots? There is no prize split at the end. We don't have a secret Blue Cabal where we play board games with Randy and use our winnings on coffee and donuts. This is classic game theory and it's being ignored.
The answer to the Vintage metagame (at least previously) was not that Blue pilots should play more maindeck cards against Shops. It's that more Blue pilots should play Shops. And that is an unfeasible reality because of player preference and card availability. The only way you can reach equilibrium is if players who are unwilling or unable to play Shops leave the format so that Shops becomes the appropriate percentage of the Vintage metagame. Compared to that, restrictions are much preferrable.
To borrow from the article, "Can we officially stop with this nonsense?"
The problem with this analysis is MTGO.
Workshops are much more widely available online and have been as high as 50% of top finishes in the past (this is almost certainly one of the major data points leading to the restriction of Workshop cards in the past couple of years)
It makes no sense to say "Shops is only 30% because they should be 50% but people just can't/won't play them" when we have evidence of people playing them at a higher rate in the not-so-distant past