I assume that they're hoping that the EU or an EU member-state steps up; or failing that, maybe a (probably-US) nonprofit or billionaire donor, perhaps a Laurene Powell Jobs or MacKenzie Scott type. To be clear, something like this very probably should happen. I'm heading to social media to shout into the void about this: dear reader, you should probably do this too, and use any other means you might have to steer the attention of decision-makers towards this.
That said, in the longer term the solution to the WWW"'s Too Big To Fork problem surely has to involve getting much more of the "specification" expressed precisely in declarative specification languages, so as to greatly reduce the handwork involved in generating a half-decent implementation.
A lot of private funding at these consultancies actually comes from pet features. Some company says "hmm, we sure do rely on XYZ feature a lot, would be nice if it were faster", they throw some money at a consultancy like Igalia, and then it becomes faster for everyone. No need for a big pot all at once, though I'm sure that'd be really nice.
I don't think a single big donation is a good idea. We're so used to seeing extreme wealth we don't event question it.
Once a big donation is given, you get to wonder what sort of influence that person (willingly or not) has had on the project. A much better model is a large amount of small donations, the incentive becomes to serve the maximum amount of these people.
I too would prefer that the funding come from a relatively hands-off source, like some EU pot, if possible. But I think that nearly any (reasonably likely) funding source would be preferable to letting Servo development fail.
That said, in the longer term the solution to the WWW"'s Too Big To Fork problem surely has to involve getting much more of the "specification" expressed precisely in declarative specification languages, so as to greatly reduce the handwork involved in generating a half-decent implementation.