These are also bad arguments:
Saying Mishra's Workshop is not literally Black Lotus conflates the meaning of the argument and ignores the intent. Mishra's Workshop creates a tempo advantage, enables Shops decks to jump the curve, and makes the modern costing of Artifacts problematic as you can't take Workshop into consideration when pricing cards for Standard. Black Lotus has a similar effect in jumping the curve and effectively powering out spells earlier than they were intended to be cast. The type restriction is not relevant to the argument being made. Whether or not you believe this should be a core part of the Vintage experience or limited via restriction is the essence of the argument, but trying to deflect the analogue away from its intent is disingenuous. @fsecco, it's pretty clear what you hate isn't "logic" because you ignored @GutoCmtt's inclusion of a type restriction in the analogy. You just had a reflexive action to what was said, which is the flaw of these B&R threads.
The argument that "Mishra's Workshop had caused a lot of cards to be restricted" is popular and not limited to Guto, but I would argue it's specious. Vintage has the limitation that a portion of many decks' manabases is composed of artifacts, which honestly makes cards like Chalice, Trinisphere, and Karn pretty incompatible with the format. I'm not sure how many people have tried Karndrazi or similar decks, but each of these cards is incredibly powerful on the play because you are forcing your opponent to play Legacy while you continue playing Vintage. When you get to cast a 4 drop on turn 1 and your opponent plays a 1 drop (or nothing because of a Sphere or Trinisphere), that's not a very interactive game of Magic. The reason Chalice Trinisphere and Karn and restricted is more a product of Moxen than a product of Mishra's Workshop. Similarly, restricting Forge is suspect given the amount of Moxen and other fast mana available in Vintage and not in other formats. Forge sees play in Legacy with the Sol lands in decks like Bomberman because of how broken it is with 0 casting cost artifacts. Having played the deck, I am skeptical that simply restricting Workshop would be enough to diminish the decks brokenness. That leaves Thorn of Amethyst and Lodestone Golem as cards that were likely restricted because of Mishra's Workshop. Maybe Memory Jar? Pretty skeptical on that one as well. In any case, I wouldn't say there are a ton of artifacts restricted just because of one card. Rather a confluence of factors contributed.
And comparing highlander Blue decks, this is a false dichotomy because people are using this to discuss specific restrictions. What restrictions are being contemplated so other Blue cards can come off the restricted list? There isn't a fix for Blue. The color is broken by Magic's history. Artifacts and graveyard based decks are arguably broken in part because of a singleton land.