Not... at all? I mean, Vim has a steep learning curve[1]. Factorio is a game meant for the masses.
Of course any game is hard to master, but in that case any game that is not made for 3 year olds has a steep learning curve. You won't know how to set up and manage a 1kspm factory from day one, but that's okay, you can start by exploring and have a lot of fun doing that.
[1] (if you ignore that you can just start by hitting "i" and save with "<esc>:wq" and you have an ordinary editor, but that's not the point.)
Mind you, compared to other “programming games” like e.g. Shenzhen I/O, the main gameplay loop of Factorio is quite a bit simpler to wrap your head around. It's only when you try to ultra-optimize everything that it reaches that level of complexity. (Or when you "program in Factorio", ala "programming in Minecraft.")
No. For example, my cousin plays it, someone who typically plays games like the Sims (and other games popular amongst women), has no university degree. She has no trouble with Factorio. I am honestly confused how anyone would call Factorio a difficult game. It's nigh impossible to lose unless you change the default settings to generate a more difficult world with much more aggressive biters. It's a building game, not a shooter that requires any kind of skill or specialised software that requires a manual.
Edit: asked said cousin whether she thought it has a steep learning curve. Answer was "lol, yes! And the curve just continues, there is still lots I could do better". I suppose having nearly only programmers as friends skewed my view of how many people had no trouble getting into it.