I'm curious how much of the popularity of RGBM is based on, "well we paid for it, we might as well use it." I can't imagine licensing it from Bruce Wienke was cheap.
Until there's a financial reason to divest themselves from RGBM, they might as well keep using it. I don't think recreational divers are any more prone to getting bent by using it, so it's not like there's a safety-driven reason to dump it (or really any other modern algorithm). I don't know any technical divers that are doing serious dives with RGBM anymore. Light deco, sure, but 6 hours in a cave or 120m on the Britannic, I don't think it's much of a contender at all. Not to say it's not used, just that it's probably nowhere near as prolific in the technical diving world as it was 10 years ago or so.
Sure, an old-style Zoop (that novo stuff can go kick rocks) running Buhlmann-GF would be fantastic, but I don't see a reason why Suunto would ever go that direction. There's just no need. Same same for other manufacturers using whatever algorithm they've chosen.
Something important to remember is that the primary drivers of Buhlmann-GF are technical divers. They are the ones that tend to tweak stuff to suit their style. Most recreational divers probably don't even adjust the conservatism settings on their computers, let alone get into the nuts and bolts of decompression models, at least enough to understand what custom GF setting they'd like to use. And the Scubaboard audience is comparatively small, so while there may be a more knowledgable user base who would desire something like this, it's probably nowhere near large enough to get a major manufacturer to throw down a new manufacturing line.
Of course this is all just rampant speculation.
@RonR would be a much better source for sure, and barring any trade secrets, I'd be interested in his insight into the continuing choice of algorithm by different manufacturers.
Also, to be clear, I think an old-style Zoop with custom GF's would make an awesome dive computer. I'd buy one for rec dives and use that instead of my Predator.