I know they didn't expand into India and the steppes cause of Russia and Persia, but why not into the rich and full of gold Ethiopia? One a side note, why not expand into Yemen and Oman, being rich trade hubs?
They did. Here's my answer: https://www.reddit.com/r/AskHistorians/comments/6v3aaa/how_did_ethiopia_survive_so_many_empires_from_the/dlyofki