Being well-capitalized makes a world of difference. I'm in retail, but I'd assume manufacturing is even worse. Being able to pay cash to my wholesalers saves me a bunch of money because I can squeeze better deals and discounts out of them. On credit, a lot of them let me do net 30. A few guys let me do net 120. But if you run out of cash, it's game over. If you don't have cash on-hand to buy grain, you can't make beer and you're SOL.
I've run the numbers for different sized operations, and if you're going to start small you have to sell consumer direct. The margin is so low on selling to liquor stores or grocery stores you'll need to make a lot of beer to make any reasonable amount of profit. The smallest size brewhouse I thought was reasonable (if you want to be able to pay yourself or any employees) was 7bbl, though 5bbl might be feasible.
Anything smaller than that and you'd need to be selling pints in a taproom, and maybe kegs to restaurants. The cost of glassware is pretty big, and from my estimates selling kegs was about as profitable, per liter, as selling 6-packs of 12oz bottles. 22oz bottles are a much better way to go, but you're talking about a bottling machine (mucho $$$) or hand-bottling (mucho time).
Also, i wouldn't plan on being able to pay yourself a salary and pay yourself back for your initial investment in fewer than 5 years.