I think Grado has "faded out" at least in the world of head-fi (both this site and more broadly "headphone hi-fi") because they haven't gone down the rabbit hole of "new-release-itis" - they don't have some new product every 6-9 months to play the tradshow circuit, and there's this insipid notion that "newer is always unequivocally and absolutely better" that's been carried over from other tech enthusiasm subgenres into the land of head-fi. Also, there's a lot of aesthetic and practical reasons (which have nothing to do with sound or performance or anything beyond someone's personal preference) that have seen Grado, as well as a lot of other "older head-fi standards" pushed aside - specifically that they aren't:
- Producing "mobile friendly" cans with iOS/Android mis/controls
- Doing anything celebrity endorsed
- Doing everything celebrity endorsed
- Having rappers and producers hawk their products
- Producing closed/noise-cancelling/etc cans
- Massively re-working their industrial design every few years (the last big change was around ten years ago, with the GS-1000 and their move to a truly "full size" platform)
Broadly this doesn't just end with Grado; there are other companies that used to have significant marketshare or brand recognition in the world of head-fi that have also seen their fortunes turn, including Bose (as I understand it, they went from basically dominating the $300+ segment to being a bit player in a relatively short period, mostly due to Beats and later the Beats + Apple merger), Sony, Ultrasone, Beyerdynamic, Koss, and AKG. In all of these cases I think its a combination of not "keeping with the time" (read: following the latest fads), not transitioning from making "headphones" to making "personal and lifestyle audio devices," and more broadly changing tastes for the market. Specifically I think people today have an expectation of isolation, loads more bass, and more connectivity with mobile devices than Grado offers. All of that said, Grado continues to revise existing models, and release new models, and has expanded into online sales (via 4OurEars), so its probably safe to assume they're doing okay financially (what I mean is, I'd be surprised if they announced they were going bankrupt and shutting down tomorrow), and will probably be with us into the future. Certainly they do still enjoy a following within head-fi, but like everything else, we've seen hyper-specialization push everything into a niche, and Grado, perhaps more than any other manufacturer, have been so thoroughly and completely type-cast as a single role pair of cans over the years ("Grados are for rock!") that it isn't surprising they don't hold center stage these days.
Personally I think they could withstand changing *some* of the above things - some of their "we do this as we've always done it" mentality I don't think serves any function (e.g. there's lots of good options for removable cables, closed headphones don't have to be bad, and new designs aren't always bad as long as it isn't done just to appease the tradeshow circuit). On the other hand, I think the tastes of the market in general have shifted, and that's through no fault on Grado's side, nor would I expect them to completely scrap their successful cans just to try and pander to "it needs a rapper's face on it, more bass than a dance club, and tons of chintzy plastic!" What I'd be curious to see is if their overall sales have changed much since the early 2000s - my guess (and this is truly just a guess) is they probably haven't, despite the overall market growing significantly in the same period. As to why I'd guess this - if they were really "in trouble" they probably would be making more dramatic changes to their offerings, both in terms of cost cutting (e.g. outsourced manufacturing, cutting corners on performance, etc) and trying to chase fads to gain sales (as many other headphone companies have done in the last few years).
Also something else, specifically related to Grado, is that they've seemingly withdrawn from participation on Head-Fi (the site) in more recent years, whereas they used to be more actively involved (and had released a few special edition cans exclusively for Head-Fi members). I don't know if this is due to their waning popularity within the community, changes in management/marketing direction, or some other factor(s), but I think it has contributed to their declining visibility on the forums here, for better or worse.
Frankly I'd say its a good thing they're still around, and still mostly carrying on business-as-usual, as it provides yet another option for good cans, and that's never bad. But change wouldn't necessarily be a bad thing either.