When people running 10 gallon systems talk about profit, they are rarely considering everything that it costs to produce and serve the beer. It is easy to make a "profit" selling beer, especially if rent, utilities, and NNN are free because it is at your house or part of another business that is paying those costs anyway, and if you are not paying yourself for the time to make or pour the beer. It's like kids with a lemonade stand who think they made $3 selling lemonade at $.25 per glass, never considering that they didn't buy the sugar, lemons, water, cups, pitcher, ice, ice maker or trays, electricity to make the ice, table, chairs, cardboard for the sign, markers for the sign, and a few other things I'm probably leaving out.
It's fine if it pays for the cost of doing business and you are doing it because you love it, but to me that is not the same as making a profit. In my book, you are not (and we will not be) profitable unless you can afford to pay someone (or yourself) a fair wage to do all of the work, pay all of the bills, put money away for maintenance when something inevitably breaks, and have a penny left over. That penny is your profit.
I know some people running nanos in my area. The only way they are "profitable" is when they do it on their own property so they have no lease costs to deal with, and several of the other costs are just part of their regular household costs. No one submeters their own garage. They also either keep their day jobs or have spouses to help pay the bills. Maybe they can pull a little money occasionally or afford to upgrade equipment, but they are not paying themselves what their time is worth. I think Mic of Dungeness Brewing is a good example here, maybe he will weigh in.
This is not meant to discourage anyone from doing it, but don't expect to make a living at it. If you think that is the right path for you and will help you build your name while you build a bigger brewery, or if you are doing it as a hobby business, go for it! There are success stories of people who started small and built a good brand that became a reliable source of income. But I ran the numbers, and for my area and the associated costs I didn't think we could make enough money for it to be my full-time job with less than a 10 bbl system.