I'm in the same situation (wife, kid, mortgage, etc). I've been working on escaping from the 9 to 5 for at least 5 years trying various different things. I have always battled with the thought that if I could only work on this full time... I don't live in Silicon Valley either. I do get very disheartened but overall I keep motivated and going. I do think of all of this as my education. Each project I try builds on the last even if indirectly.

I now have a side project that is growing pretty consistently. It took me at least a year to realize that this could really be something. Over that time there have been periods where I have given up and not put much time into it. So far I've always come back. I can now look back and see that the months I gave up revenue stagnated. I can also clearly see what I did that increases revenue. I can also see that if I keep working at the same rate (some evenings and some weekends) and revenue increases at the same rate that it should grow into something that will replace the 9 to 5 in the near future. That is particularly exciting to me as I want a business without the stress, complications and long hours. I now look forward to not working full time on it.

So keep at it. Something your working on now maybe the solution. It doesn't have to be big and exciting. There's plenty of people trying the same. It's not easy for sure but certainly doable.