Hey there,

Just to let you know, your question is fine, and we're letting it stand. However, you should be aware that questions framed as 'Why didn't X do Y' relatively often don't get an answer that meets our standards (in our experience as moderators). There are a few reasons for this. Firstly, it often can be difficult to prove the counterfactual: historians know much more about what happened than what might have happened. Secondly, 'why didn't X do Y' questions are sometimes phrased in an ahistorical way. It's worth remembering that people in the past couldn't see into the future, and they generally didn't have all the information we now have about their situations; things that look obvious now didn't necessarily look that way at the time.

If you end up not getting a response after a day or two, consider asking a new question focusing instead on why what happened did happen (rather than why what didn't happen didn't happen) - this kind of question is more likely to get a response in our experience. Hope this helps!

Aside from flavor issues you CAN make alcohol with a mash bill of 100% corn but not having at least some barley in there makes the whole process a lot harder. Barley has a lot higher diastatic power than corn (which means the ability to convert the starches in grain into sugars that yeast can consume and turn into sugars) so putting some barley into the mash makes it a lot easier to efficiently convert the grain into something that the yeast can eat. Of course with modern technology it's easy to simply add the enzymes that convert the corn but there's no real market for "100% corn booze" so why bother when you can get by with just a bit of barley?

Source: Chaudhary, Dharam & Kumar, D. & Verma, Ramesh & Langyan, Sapna & Sangwan, Seema. (2013). Maize Malting: Retrospect and Prospect. Maize: Nutrition Dynamics and Novel Uses.