The way of a loner, fiction or reality?

I am a programmer and a designer and many other things, I tried to implement my ideas as a loner, but design and development is not all that a project needs, almost any project for people or business requires registration and promotion, support and investment. I've been able to create small projects alone, but I've never been able to do anything bigger. For example, one of these projects is a browser extension: https://chrome.google.com/websto... Please share your opinion, experience and examples of people who managed to do something alone, let's put it in its place and finally put an end to whether it is possible or not.