For better and for worse, Warhammer Fantasy is a setting where there are exceptional individuals who can achieve things that are impossible under normal circumstances. The fundamental metaphysics of the setting bend around the existence of Lords and Heroes who can individually change the fate of entire battles. Gods are undeniably and blatantly active in the world and intervening to the benefit of individuals they favour, and there are forms of matter and energy that actively foil the concept of scientific rigor.
The factions of the setting can be examined through the lens of how they deal with this. The 'standard' way is to focus on creating militant heroes, the most directly useful kind, by having a professional warrior class trained from birth as well as exposing the rest of the population to enough violence for any 'natural' heroes to show themselves, and then enough class mobility to elevate them to make use of their gifts. This is how the Imperial Tribes worked, this is how Kislev works. Bretonnia is arguably at war with this dynamic, but depending on how much Joan of Arc and 'I looked through the archive and it turns out that Peasant Really Good At Stabbing is actually a bastard offshoot of a noble family!' you read into their dynamic, it could be that they're working in harmony with it.
The High Elves try to make everyone a hero. The Dark Elves make it so that anyone that is a hero can swiftly backstab their way to the top. The Skaven put their population into situations where the only way to survive is to be a hero. The Lizardmen have plaques that tell them when the next lot of heroes - a 'sacred spawning' - is going to clamber out of the pools. All greenskins think they're the hero of their story, and a lot of them turn out to be right. The Ogres have outright codified this outright into their 'Big Name' cultural dynamic. And Chaos, of course, revolves around it. The faceless masses matter so little that their logistics don't even bother to make sense. What matters is the Heroes - the Chosen. And what matters most of all are the intricate rituals around the selection and the coronation of an Everchosen.
The Dwarves, as is their nature, largely refuse to bend to this system and instead try to bend it to their purposes. Dwarven heroes are almost always leaders and artisans. The only time they lean into the whole thing is when they wish to die. To be a Slayer is for them to surrender themself to the ugly truth of the world, where individuals stand against hordes and beasts, and ride it to as many slain enemies as it allows them, until it grows bored of them and grants them death. The rest of the time they stand in shieldwalls and firing lines, with the rank-and-file wielding the weapons crafted by the heroes and following the orders shouted by them.
The Empire, deeply influenced by the Dwarves as it is, is an attempt to marry the two approaches. On one hand you have the sacred: the Knightly Orders, the Warrior-Knights, the Witch Hunters. On the other you have the secular: the shieldwalls, crossbows, the handguns, the cannon. 'Faith, Steel, and Gunpowder' are the three pillars of the Empire: the faith and steel of the knights, and the steel and gunpowder of the engineers. This dynamic is perhaps strongest of all with the Colleges because they interface directly with the energies that make the world what it is. The heroes charge forward into the impossible, and then when reality bends the rules for them, they shout 'no backsies' and try to wrestle what just happened onto parchment and into something reproducible. This is what codifying is.
This doesn't always work. Every great Wizard leaves a trail of Fozzrick's Flying School memes in their path.
If Mathilde had just wanted to make one Waystone, she could have banged that out in maybe a couple of actions. The reason that what she's doing is hard, and why it hasn't been done before, is that Mathilde needs to gather together heroes and then have them work against what they know works best and instead carefully and laboriously blaze carefully-marked trails that anyone can follow.