What is more difficult to make: beer or wine?
I haven't done it myself, but I guess making beer is more difficult for one good reason: safety!

Grapes will ferment by themselves and will produce either wine or vinegar. The fermentation process is violent, so there's no risk. Added meat will be fermented as well!

Beer needs to be sterilized before a yeast is added and there's a risk for butulism.

Now, making a good wine is something else. I guess that making a good wine is far more complicated then making a decent beer, once you overcome the safety issues, as there are a great number of steps involved in making good wine. For instance: aging in oak.

Commercial wines start by sterilizing the grapes and afterwards adding a certain yeast strain, but hey...