Money is less important to them than preserving and cultivating their catalogue in a way that satisfies themselves and their legacies
I don't read it that way. They are putting up the rights to their masters and brand rights, that means they would likely need to give up a sizable amount of control. I doubt any conglomerate is gonna give you 500 million and then say "you just tell us what you want and don't want to release for us to recoup the purchase price".
And shrewdly, they want to retain publishing rights so the big payday isn't the end of the income stream.
I agree with that. But given the balance of power in the band (and let’s still call them a band, even though it’s more an entity that curates the legacy and does the odd thing for charity) it’s hard to see there being much impetus for anything relating to The Wall or The Final Cut, much as I’d love 5.1 versions of each of them.
If anything for fans, I would see this as being good thing for thinking 5.1s of other titles will see the light of day. No one would be shelling out the money if they were just satisfied with the back catalog sales. The down side may be that the new controlling interests may think Guthrie or Jackson isn't with the money on a 5.1 remix.