They keep dying, and they will keep dying. We will keep dying, I hope not too fast.
Keith Emerson was one third of a supergroup power trio that was huge in the early 70s, riding a crest of progressive pseudo-classical rock (along with Yes, Pink Floyd, Jethro Tull, the Moody Blues, King Crimson and many others) in the maw of punk. And then they were over, for a while.
ELP were notable for some very good songs, like this one, which includes a striking acoustic guitar part by Greg Lake, and also monstrous bombast at times, which was all part of the fun. These guys were rock stars at the height of rock stardom as an unalloyed privilege, which only makes them figuratively immortal.