Yes, Minecraft is dying. This game has been popular for many, many years and I don't blame it for decreasing in popularity. Everyone that played it is getting older, growing more mature, and are probably too caught up with real life to continue to play it. All servers die eventually, as well as games, so it's not a huge surprise that Minecraft's popularity is going downhill.
Hypixel first of all is losing players but not very many, there have just been fluctuations of players throughout the year. Any new players that start to play Minecraft are now playing on the newer versions for a start as they wouldn’t think Tom go back to the older versions which makes sense. A lot of servers still run mainly around 1.8 (which I love) but it means only a few servers are getting those newer players. Also generally (this is a presumption) more people are playing PE than PC probably as less people see the need to buy a PC these days with many people getting consoles or Apple devices so they decide to play on those versions of the game. Older servers now are basically fuelled by the fact that older players are still playing the game. To be honest, that all said, I think we should just get on and enjoy the game while it lasts rather than worrying about its future just yet.