Or you are being entirely unreasonable and ignoring evidence which goes against your conclusion, no one else has the safety nets we do to try this experiments with out getting screwed to fast to pull anything off.
So the fact people tried in the past is utterly irrelevant. They ended up crazy due to dhar exposure, the belt stops that, also calling some one a troll whilst completely ignoring what they are saying is pretty damn rude.
So to build on this lets describe what earlier experiments with multi-wind actually were because we have some WoG.
Now as context the way magic typically works is that the caster uses their soul as a nexus point drawing in the wind or winds of magic (If you're a swanky elf or slaan, alternatively if you're a crazy dhar using megolomaniac) they intend to use and shape spells via their willpower and their souls. Previous multi wind experiments in the college that we've been told about involved channelling one wind of magic, detoxing and then channelling the second wind of magic. All attempts to things this way ended up with corrupted casters that ended up on the dhar path.
from this we can learn/infer two things, channelling the winds of magic even if they don't create arcane marks will still have micro effects on the soul involved which makes small bits of dhar get created as the human soul is likely to mutable. Secondly that channelling more than one wind is never viable as a human even if you avoid arcane marks, at least with collegiate techniques that were created by Teclis (WOG here is that Teclis created a tradition of magic to make humans better able to mono focus winds.
We know that past human magisters didn't have the tools Mathilde does, we also know that the first 30 years of the colleges was mostly frontier journeying and combat with academic experimentation likely being at a minimum. We also know that for another thirty years the colleges of magic were banned again. So the amount of time the Colleges of magic have actually had to do pure experimentation is not nearly as long as you would think from the length of their existence. Wind-Wind interactions were soft-banned very early on because of the dangers of creating dhar and aren't allowed unless you've a good idea on how to circumvent dhar creation.
So to summarise, early multi-wind experiments were channelling (Not what we want) didn't have safety tools, and there wasn't nearly as much time that could have been dedicated to the potential research project.
So that covers the past but what about the future.
Mathilde has four things going for her that the average Magister (that is full blown wizard, not just journeyman) doesn't. She has magical senses as acute as Volans, She has a belt which destroys dhar before it can impact her even if she were to hug a daemon or juggle warpstone. She has a dwarven tower which blocks all the outside winds of magic allowing her to run magical tests with no outside interference so she can see more clearly what does and doesn't work and why and lastly she has the fundamental understanding of how necromancy uses Shyish tongs to manipulate dhar.
We know that the winds of magic interact in the wild naturally with out producing dhar, that's evidence of why it should be possible to influence one wind of magic with another with out creating dhar. High magic is an example of all eight winds being use concurrently and not making dhar (Softer evidence, i'll grant due to the possibility that it only matters if all eight are used)
I have to go for about an hour will edit post with more when I can.