They are. At Minecon today they announced a beta for the Windows 10 version of Minecraft. It's a port from the Pocket Edition version of the game.
More info: http://news.xbox.com/2015/07/games-announcing-minecraft-wind...
More info: http://news.xbox.com/2015/07/games-announcing-minecraft-wind...
"I really wish Microsoft, will some day push Mojang to rewrite Minecraft in a different language while keeping it portable."
From the article, it looks like the rewrite would not affect linux/*nix users. If I get paranoid, I'd say they might even drop the "old" client at some point.