Is there a reason SE is not trying to future proof content AT ALL?

[OvernightSiren]

Fates/CEs scale to the number of people in the instance so it'll be fine even if it's not packed. It's also a super effective way to level 71-80 so I'm sure there will always be some amount of people in there.

That's probably way more future proof than Eureka ever was/is.

Not really, considering people still go into Eureka to this day because Eureka had:

1) Mounts that are actually rare. Meanwhile the gabriel mount is way too common

2) Bunny fates with unique hair, emotes and mounts

3) Lockboxes with unique mounts and glamour items (while Bozja's stuff is just the gabriel mount and then a bunch of crafted items you can easily get from old primals)

4) It was the only way to get the SB relic, meanwhile for most of the steps for the ShB relic (especially after nerfs) doing nearly anything related to Bozja is the less effective way to get the relic compared to just doing fates in old zones

5) BA, which has benefits to running it multiple times meanwhile Delubrum Savage does not. It's a one-and-done instance.