The game's legendary difficulty is entirely due to the impenetrability of its user interface and systems. When you actually finish getting through all the tutorials needed to learn how to play the game it falls flat on its face. It is quite trivial then to get a fortress up and running and produce far more food, drinks, and goods than you ever need and grow your wealth rapidly. And then when the enemy comes knocking it's quite trivial to pull up your drawbridges and line the entry halls with traps and generally grind them into a smooth red paste.
Dwarf Fortress may be a fine simulation and an interesting study in systems and a great conversation piece but it is not a very good game. It is like the Great Salt Lake of games: a hundred miles wide and a few feet deep.