Maybe i am wrong but it looks like we are not talking about the same thing : you are talking about influence of shop restriction in the actual meta whereas i am talking about influence of shop restriction in an hypothetical and mostly unknown meta related to a set of rules for B&R (opening post).
I have witnessed enough shops match ups to know that they often have superfluous mana and have plenty of games where they win on sol lands. Shops already did not come up as frequently as that deck wanted and it still dominated for years. The decks most critical drops have always been and are still are 0 and 2 drops, nothing changes there either.
When you witnessed shop matchup, did you see mulligan choices ? Because it is what is at stake here (later in the game you are right : shop has lot of useless mana). Most of the time, an opening hand with one ancient tomb and lock pieces is a mulligan. Of course, it depends on what you know about your opponent and the other cards in hands but most of the time it is the good choice.
I don't know if you ever played shop but if you did you must know that match up where opponent is running wastelands are very different to ones where he is not. There is a reason for that.
I don't see why you need to throw the baby out with the bath water and redesign the deck from the ground up. We know through heuristics and our observational knowledge that the deck not only still works but is also still competent at doing what it does. We also know that the decks largest predator right now is not mana but rather a free green spell that does not care about your mana.
How good the deck is in the meta has not actually been about the card workshop for some time, it's about the hate that is played and if it can get in under that in the first place. Shops is not good because of 3 mana, it is good because you do not take damage/lose a card/etc to use it. If eldrazi were to become the better of the deck it is almost undoubtably because of other factors.
I agree with what you said but you should go further down that road. The real question is about which deck is stronger ?Deck 1 : is running 40 artifacts and made some little adjustements to take in account there is only 1 shop. Basically, the usual shop deck. Deck 2 : is running (let's say) 25 artifacts and 15 [add here what you prefer : Eldrazi / blue spoilers / one or several colors / whatever].
My point is that both decks can be played and would be competitive but the deck 1 would be suboptimal compared to deck 2. Reasons are simple : less artifacts mean less relying on singleton workshop, and also means that the nasty free green card will be less devastating. Basically, deck 2 is less sensitive to artifact hate and could potentially have access to blue power, cantrips, draw effects, ... (whatever) , in short strong new effects.
If you ever played brown and colored shop deck, you must know that dynamic of those decks is very different.
@evouga This is a good analysis. I would actually argue the metric to track is not number of cards over time in total (unless I am misinterpreting this) but rather new cards released per year, or perhaps product releases per year.
The reason I say that is because first and foremost, cards that are designed already do not necessarily make the design process more taxing. When they designed the 275ish cards in Ikoria the fact that alpha exists probably did not affect the level of effort.
The thing about the graph you put together is that there are MANY years where there were 0 B&Rs but you maintain the level they are at. It's not about current sum total but rather the difference year to year in how many they have had to make.
My contention of course is that the more new products (not just sets) they try to release, the more mistakes they are making disproportionately to when we had a fairly static 4 sets + maybe a commander release a year. Size of the sets probably also factors in as designing Ikoria with a partner Commander release was well more taxing than designing just a stand alone, but there are any number of ways to shake out the metric.
Divination is a great card when your hand is empty at the end of the game.
I mean, if you plot a chart of the admitted mistakes, bannings and restrictions and errata they have had over the past few years, and put it against a chart of the increase in releases the game has had, it's pretty much a direct correlation.
Ok, that's an interesting question so I looked into it.
Here's a plot total unique card printings over time, along with the cumulative number of cards that have been banned or restricted in Standard (or whatever the Standard-equivalent format was at the time):
The rate of new printings has been slowly increasing throughout the game's history. Despite this, the rate of Standard restrictions plummeted to nearly zero, until something went wrong starting in 2017.
I manually scraped the restriction data from the MTG wiki timeline. Tabulating the number of new printings over time was surprisingly annoying; I wrote a script to compute this using the Scryfall API.