Armory’s render is completely different than the Blender one. It has nothing to do with Eevee, other than the fact that Armory is calibrated to look similar to Eevee so that your game looks the same as in Blender when you run it.
Armory runs on top of a low-level game framework called Kha which is what allows for its incredible cross-platform ability. Armory is actually a collection of libraries that work with Kha, including a custom renderer and game engine, along with the Blender plugin that exports your blender scene to a Kha game. See this doc to get a full overview of the architecture.
A big reason for not using Eevee is that it is a part of Blender, which is licensed under GPL, which doesn’t play very well with commercial games.