We should do what we need to do to spread is as widely as possible. If attaching a price tag limits our ability to spread it even a little, we should not. If they want to pay us even though they don't have to like the Asur are, sure, great for us, but it shouldn't be conditional.
I'm astounded you'd go so far as to make a claim so brazenly false as that it'd be extremely rude to the people who worked on the project. Those project members knew and accepted from the start that we'd seek to spread the benefits as widely as possible, which is why we told the Bretonnians we'd spread the benefits as widely as possible. Or am I to believe that Mathilde was lying to the Bretonnians? That all along, she knew the project members would get upset if we drained the world of as much harmful magic as possible, and then lied to look good for the purposes of diplomacy.
Okay. You get what you give.
If Bretonnia ends up unwilling to pay for the results of the intellectual labor of several prominent researchers in the quest (I'm like 90% sure it won't happen), then Mathilde gotta prioritize like any reasonable person.
First is Kislev and the worst parts of the Empire, no matter what: Kislev is on the frontline, and the Empire has contributed the most people, including the project lead. The Karaz Ankor network is a touchy subject, so I'm certain Mathilde will approach it carefully, ensure they have the ability to expand their network (including, of course, hiring wizard labor from the Empire if the need is unavoidable; it's unlikely to be). Laurelorn is half here for the diplomacy - even their lornalim troubles were basically solved by making friends - but the other half is them expanding
their piece, because at the very least the Grey Lords have a use for the energies. And also ensuring their safety, which neatly coincides with the goal to reclaim the Forest of Shadows for the local Halethans, who have also stuck their neck out to help the project and thus deserve its benefits.
(We could ask Bretonnia for help here, continuing the trend of putting boons to benevolent uses, but you're defending dealing with the kind of Bretonnia that'd demand the fruits of our work for free, so let's continue.)
Kislev and the Empire are large and full of dangers, so even shoring up the worst parts will take a while - both only have so much wizard/witchpower. It could go faster with Bretonnian military assistance, and then we'd move on to teaching them in detail how to do the things we've sunk a whole lot of time and resources into inventing, but alas. Next priority is moderately bad areas, which are still, of course, unfun and dangerous to live in. We might get sidetracked a little on where exactly the lines go, who gets access to what, and various shinies that can be powered by the newly built parts of the network. We might also get distracted by dealing with the issue of Marienburg being a bottleneck.
A lot of time will have passed, and if the next Chaos War happens in-between, maybe half again as much, before we get to the idealistic goal of dotting ALL of the Old World with Waystones and go give them to Bretonnia. Because a version of it that is truly selfish enough to refuse to pay the people who had gone out of their way to develop this would automatically fall to the last place in the priority list.
A noble end goal is an entirely separate beast from the realities of here and now, and of reciprocal relationships.
(Edit: I'm curious what people use the Winter reaction for. Is it, like, "chill out", or "damn, that's cold", or "Kislev got mentioned!" or something else?)