I think that edition changes are fundamentally a bad thing. Corrections, slight revisions, new covers? Cool. Big changes that invalidate previous material and/or playstyles? Not cool.
This is where what works commercially and what works artistically are in conflict. I would love it if the D&D that was still in print was still some version of AD&D, either in a modern format or (preferably) the original format preserved (like a lot of classic comics get 'facsimile' editions these days). I would love it if the same was true for MERP/Rolemaster, Cyberpunk, and WFRP as well.
Particularly as the market leader, D&D has unique pressures on it to both i) update in search of new potential markets and ii) reformat in search of re-purchases from its existing markets. 'Malibu Stacy has a new hat'. It's unfortunate but it's largely inevitable.
I think the notion that this coming D&D will be evergreen is naive. The people in charge of D&D now won't still be in charge of D&D in ten years time. I don't mean it won't still be owned by Hasbro, because it will, but that the people inside Hasbro/WotC will have changed. Also the market will have changed, and sales will to some degree or another have stagnated, and Hasbro's ambitions for the brand may have changed. Eventually Malibu D&D will always need a new hat no matter how perfectly the old hat fitted.