This has been talked about before and in here as well, but to try and keep it short, it's not impossible but very difficult, and you need to really work hard to find your first customer(s).

Then, continuously keep in touch to ensure you're building and tweaking the product according to their needs, not what _you think_ is important.

It's mostly customer support and business development work, not as much development/engineering, which is what most software engineers believe and hope it to be.