How many turns of phrase do you use that you know the full origin of. The issue is, because the Jedi have been the focus of Star Wars for so long, that it over states just how big and known in the galaxy they were. They were mysterious and mythic people even during the Clone Wars. I mean, the Mandos have been gone for less of the time than the Jedi, and look at how people treat actually meeting the Mando.
Yes indeed... Look at how EVERYONE knows about Mandalorians, their culture and history. Multiple characters have used that to manipulate him even in both seasons.
We're the Mandos EVER as wide spread and well known as the Jedi?
My thinking is... Jedis got around in their duties. At the end they were literally generals in a pretty important war to galactic politics pre-Empire.
Say you are on a planet that the Republic dispatched Jedis to for whatever reason in the year right before Skywalker's turn. A 10ish year old kid there who was aware of or witnessed whatever deed the Jedis did would be how old by MANDALORIAN? Around mid 40ish, no? This wouldn't be ancient history or even comparable to someone now being unfamiliar with say WWI or WWII history and figures. It's like an adult now over the age of 30 not being aware of the Vietnam War or Watergate. Do those oblivious people exist? Sure. They ain't the majority and even with an oppressive government doing its best there is no way to completely purge the memory of everyone.
I mean I turned 44 over the summer... My mother (1949) and my grandmother (1932) are still alive. There isn't anyone alive 5 years after Endor who remembers the Galactic Republic's seeming only guardians of Peace and Justice and who did so in a rather flamboyant way (Lazer swords and robes) based out of a giant tower on the capital planet with the backing and blessing of the near galactic wide government, who on top of that were the most visible adherents to a religious philosophy whose tenets and beliefs are so ingrained into the culture of the Republic that sayings like "May the Force be with you" are as ubiquitous as "God bless you" in the real world?
I don't buy it, but more importantly it makes no sense in that this inconsistency... Doesn't do anything for the story. If in the story Mando from the jump was "I don't know what species this child is... But it has the Force. Like the Jedi of old. But the Jedi are no more."
Then the armorer could reveal that no, the story of the fall of the Emperor includes the last known Jedi. That Jedi has now gone on to refound the order in secret (I honestly would assume the New Republic would set up Luke wherever he wanted but keep the location close to the vest.) but no one knows where.
Nothing major has changed in our story this way, has it? Mando is still searching for the Jedi either way, no?
So what has making this highly unlikely mass amnesia about the Jedi Order added exactly? Galaxy wide anyone over 40 years old should have memories of the Republic and the Jedi. There is no way around this, especially since, outer rim or not, Mando gets around. This would all be fairly common knowledge one would think especially in the circles Mando walks in. Warriors, assassins, criminal elements... The legends if not the history of the Jedi would factor into the various groups that the Jedi confronted on a regular basis as the defacto Federal law enforcement if you will of the Old Republic.
Lastly, our Mando in this series has got a Spock thing going on. Because of Spock's half human heritage Spock tries to be the most Vulcan Vulcan of them all. The chip on his shoulder about his human side makes him go to great lengths to emphasize his Vulcaness. I think our Mando has a similar thing going on. As a foundling he wasn't born into the Mandalorian world or culture but it is pretty obvious once he bought in, he bought in hard. He's committed to the Mandalorian ethos and is well, well versed in their ways and seems pretty informed on their history... But he just skipped all the history between the Jedi and the Mandalorians? The Dark Saber? None of this came across his desk?
It is just something that sticks out and makes no sense, especially given how good everything else on the show is this aspect feels like the person that came up with it DOESN'T know Star Wars... Which is impossible given the pedigree of the people behind the scenes. So... It's always gonna make me and I dare say a lot of other SW fans scratch our heads.