So I do think SQEX could demonstrably do a little better at future-proofing some things here and incentivizing people to keep the older stuff alive for the newer players following along behind us: add weekly challenge log entries for critical engagements, put Delubrum Reginae into Wondrous Tails, make some of these sort of things give current capped tomestones if you run them with a level-capped character, etc.

I mean, they demonstrably know this does keep older content alive, because they incentivize specific instances of older content in that way already with Wondrous Tails, as well as incentivizing filling whatever older content needs people with daily roulettes.

It's just particularly unfortunate that the content which is poorly incentivized and so sort-of dies off happens to also generally be the best candidates we currently have for "the intermediate step(s) between the difficulty of the MSQ and that of higher-end stuff like savage".
1000% agree.

It also makes it harder when later on you feel like going back to do it for the fun of it..and its a ghost town.