From http://www.paulgraham.com/startupfaq.html:
How can someone start a startup if they have a family to support?
The best plan might be to start a consulting business that you can gradually morph into a startup. This way you always have a source of income. See How to Fund a Startup, especially the section labelled "Consulting."
So what exactly are you saying I'm mistaken about? Can you give me a specific sentence I've written somewhere that you believe is false?
First, this is what you actually have to say about consulting companies:
But isn't the consulting company itself startup? No, not generally. A company has to be more than small and newly founded to be a startup. There are millions of small businesses in America, but only a few thousand are startups.
So, first, whatever it is you actually think about using consulting services as a vector for getting product to market, you explicitly define those companies out of startupdom --- both by answering "no" to the question of whether they're startups, and by supplementing your definition with "small and newly founded".
Second, while you're kind enough to suggest that consulting might be a good way to start a company for those of that have families, the majority of the "consulting" section of the essay you cite consists of warnings about the perils of consulting.
In fact, you're even more explicit in another essay:
This one is real. I wouldn't advise anyone with a family to start a startup. I'm not saying it's a bad idea, just that I don't want to take responsibility for advising it. I'm willing to take responsibility for telling 22 year olds to start startups. So what if they fail? They'll learn a lot, and that job at Microsoft will still be waiting for them if they need it. But I'm not prepared to cross moms.
What you can do, if you have a family and want to start a startup, is start a consulting business you can then gradually turn into a product business. Empirically the chances of pulling that off seem very small. You're never going to produce Google this way. But at least you'll never be without an income."
Or, how about "Ramen profitable", where you say:
Is there a downside to ramen profitability? Probably the biggest danger is that it might turn you into a consulting firm. Startups have to be product companies, in the sense of making a single thing that everyone uses. The defining quality of startups is that they grow fast, and consulting just can't scale the way a product can. [3] But it's pretty easy to make $3000 a month consulting; in fact, that would be a low rate for contract programming. So there could be a temptation to slide into consulting, and telling yourselves you're a ramen profitable startup, when in fact you're not a startup at all.
(Same essay: "it's OK to do a little consulting work at first".)
But whatever! Whether you hold consulting companies in equal esteem with shoot-the-moon product startups is beside my point, which is simply that I don't think think it's reasonable to classify companies principally by whether they are small and recently-founded. Have you ever seen 37signals offices? They're a startup.
Please, please, just explain what statement of mine you're cleverly refuting here.