Strictly a hobby for me. My guess is the failure rate for commercial brewers is probably above 95%.
In the most recent issue of Taps magazine, I saw that number closer to 25% in 5 years. I'm not sure if that is a worldwide figure or just in Canada. I know in the technology field, the failure rate is 95% within 1 year, mostly due to under capitalization, but much to do with just simply too much risk in the product itself.
Beer itself is inherently a low risk business compared to the other kinds of businesses out there, but because of the nature of the market. An example here in Alberta is that we consume around 300,000,000 liters (just under 2.6m bbl)of beer annually. Unfortunately in Alberta, doing a startup brewery is difficult because from the first day you fire up your brewery, you have to be pumping out 500,000 liters (4273 bbl) of beer within 18 months, then maintaining that minimum consistently year after year.
So yah, here you will be brewing a lot of beer to start, but you had better have your mind on marketing and sales in a hurry otherwise you will lose your license and go under in a hurry.
Having said that, I think I'm in the minority here. I got into home brewing with the ultimate goal of starting my own brewery. I'm a serial entrepreneur, so I like business, and I like that beer is a significantly lower risk than anything else I've done, and... well I just simply love beer. The idea of building a brand, telling a story, supporting local business and farmers is really exciting, and doing my damnedest to make sure the flavor of the beer backs up the business that is supporting it. And of course, build a great team to support the business.