I mean, as far as I understand it, in terms of funding Sustrans may as well be a public body that people sometimes post their pocket money to, so clearly there is some appetite for public spending on this sort of thing, however it's constituted. Perhaps being a charity makes it easier to get things done somehow, but then why are all other types of infrastructure not getting on the bandwagon? The Queensferry Crossing was not delivered by Bridgetrans, nor is the A9 upgrade being delivered by Cartrans.
As Rob says, maybe this is all missing the point - perhaps it's wrong to focus on the Big Campaigning Picture and look at the immediate impacts.
Will this cause the cancellation of any existing Sustrans investment? No.
Will this tear out any physical infrastructure (excluding signage), regardless of quality? No.
Does this prevent Sustrans having an aspirational (and probably more direct) national route map outlining key 'missing links'? No.
Will this wipe all knowledge of the existing routes off the face of the earth, or prevent Sustrans or others from advertising them in some other way? No.
Will this make it easier and more pleasant to plan routes if I can trust that any given NCN route will well surfaced, well signed and obstruction free? Yes.
Entirely selfishly, I wonder if the last one is all I really care about by this point.