I would like to clarify some of the points I made in my previous post. It might sounds that any app has to be developed in 2-3 days by single guy. Kind of, it does.
# About time
What you are doing is that initial development is really in short period of time, like before mentioned 2-3 days. Now, some apps are simply more complex and have a lot of small quirks. Then you develop skeleton app and work on details in next month or two.
I am not really a big fan of projects that require 6 months. Six months in internet time is huge. I prefer things that can be made faster. Also, this is very intense work, you will not be able to sustain it for more then a week and 2-3 days is optimal.
After initial development, then a lot of time can be spent doing a/b testing, adding meat to the bones of skeleton app.
For most webapps, initial timeline is all it is needed.. Games as a rule need 2-3 months at least, or that is impression I got. Anything else, corporate software, can be done faster, but due to corporate bureaucracy, most likely will take very long time and cost a lot of money.
Again, this is a good way to develop apps for startups.