Of course this doesn't even account for the time spent doing bug testing, and then maybe cleaning up your code. And this of course assumes that your spec for the project was able to provide say 80% of the features that someone else is looking for to use.
So yes if you're looking for a cash exit you just wasted 1.5 years of your life.
On the flip side you can look at this as a learning experience and maybe draw the following lessons:
- Start with a small side project, and once you figure out what that is make it smaller.
- Real artists ship.
- Don't reinvent the wheel and do something that's already out there.