When you had the fire-breathing ender dragons update, it became clear that the original version was going to stay separate.
However, I always suspected that they would stay separate since you can make your own skins and the fact that there are so many client-side mods available to the Java version. Client-side mods don't port; you're never going to play modded classics like the Aether, the Twilight Forest, Agrarian Skies, or Tekkit on your console because the mods would have to be recoded, which isn't going to happen both because Microsoft doesn't want their proprietary code to be susceptible to hacking and because the modding community is entirely voluntary. Mod authors have no obligation to write their code all over again in a different language on top of a different framework just for you, and Microsoft is under no obligation to share its code, especially when there's already a semi-open-source version available.
I mean, why do you think they're flirting with the idea of a "community version" of Minecraft? The vast majority of Minecraft Java's content was created by the players. That includes not just mods, but also readily portable save files/maps, re-textures, server management tools, graphic & audio overhauls, skins, development API suites, command-block chains, all created voluntarily and at no cost to the user or the creator.
Microsoft official will not put nearly as much work into the game as the players did because the sheer volume of content is far too much for them to provide without hiking the prices way up. The Java version may not be the one selling right now, but it has a treasure trove of community-made content that Microsoft just can't support.