I don't think #bluesky has died a slow death....yet. The problem is that nobody can get on and use it, other than an elite group of folks who somehow snagged a coveted invite (seriously....how?). Why would a platform that people can't actually try out make any kind of mainstream waves?
I think #Meta was smart to just push "go" and let everyone pile in. Sometimes a very slow ramp-up doesn't work to create hype. Find your critical mass and THEN figure out the details.