You have to go pretty broad-strokes for that philosophy to apply to the Realms (retcons almost nothing, advances the setting while remaining inclusive of all previous editions' canon), Eberron (retcons very little, inclusive of all previous editions' canon), Ravenloft (reboots almost everything, intentionally contradicts previous editions' canon in many instances), Spelljammer (reboots cosmology, vaguely follows 2E canon otherwise), and Dragonlance (rolls back timeline, changes some largely rules-based things, prefers to hide trouble stuff rather than contradict it).
Considering the above, it's very hard to believe their philosophy has been consistent at all during the nine years of 5E. Especially considering the 2014 5E rulebooks (and some early adventures) clearly assumed you'd just directly work from older setting lore, to include novels and video games as canon.
Forgotten Realms is a reboot, they just did it via a vaguely defined RSE and then ignored everything else. Every character that should be dead due to the 100 year time jump is alive, even the humans. The continent is back to looking like pre-Spellplague. Every deity ever killed is alive. Every city, town or village destroyed is rebuilt. The lasting effects of the Spellplague and Returned Abeir can fill a sticky note. Just because they kept the calendar year in 1490 didn't mean they basically returned the status quo to 1380.
Eberron never needed any changes, it's basically the same setting with a few corner edge cases. They downplayed the eladrin due to them not being a PHB race anymore, returned the dragonmarks to their original races, and went back to the original Planar arrangement. And they still managed to retcon Mhor Holds dwarves and their relationship with the Daelkyr.
Spelljammer replaced the phlostigen with 4e's astral sea and it makes the Elven Imperium a particular subgroup of astral elves. Dragonlance is reset to the War of the Lance with exceptions made to allow 5e player options (and to make kender less troublesome at the table). Ravenloft was rebuilt to go back to the "Weekend in Hell" style rather than the nonsensical "we're a regular campaign setting, except when we're not" design, and Planescape is basically a reset that borrows ideas from later work (like the Minds Eye) and makes some adjustments to the Factions. And prior to all that, 4e Dark Sun was rebooted to the first box but with added player options.
The core design principle is the same:
1. Reset and/or stop the timeline to the particular fixed point and keep it there.
2. Open the setting to the maximum amount of PC options that don't directly contradict the setting.
3. Keep as many of the best things as possible.
4. Incorporate elements from prior editions, including 4e.
5. Change things that were problematic, disliked, or don't agree with the current design paradigm.
6. Do not be beholden to decades of metaplot.
If you think of this as a scale, where Eberron is on the "very little work needed to get it up to our current standard" and Ravenloft as "extensive rework needed to meet our current design philosophy" you'll see every setting falls somewhere on that line.