The primary factor is money; any legalities are easily dealt with with enough money. Also, as someone else mentioned, there's the motivation. Running any business is a lot of work, and this is a hobby for most people. I have a love/hate thing for brewing, so maybe it would work for me.
Of course, I have no money to start such a business, so motivation isn't even a factor at this point.
I can appreciate your apparent desire. I'm the last person who would seek to quell one's dreams, but even if you were an experienced brewer that had 50 grand or so burning a hole in your pocket, 10-14 months is impossibly optimistic; it would probably take that long (or longer) just to cut through all the red tape of permits, licensing, etc. Laws vary from state to state, but generally speaking, you can't just brew beer in your garage or basement and sell it. Even if you could, you'd need a system large and efficient enough to make it worth your while. Basically, you need some sort of commercial property, with approval from the local zoning board, along with all the permits from the local, state, and federal government. This location would need to meet any applicable health codes - think commercial kitchen. IF you can acquire an existing bar or restaurant, that might put you ahead of the game if a brewpub is what you're looking for, but that's really a whole different animal. In Illinois there are various licenses and associated fees for breweries, distributors, brewpubs, etc. You'd have to research what laws apply for your location.
Anyway, this subject has been discussed here and elsewhere by people more knowledgeable than myself. To get some more insight into the biz, you can check out probrewer.com. If you truly have the desire, then by all means, go for it. Just be aware of what such an endeavour entails.