> Considering there is very little moat left in software and big companies can copy your product in no time?

Your task in a software startup (or any startup) is to produce the moat. If you can create something with little effort in a few weeks or months then so can anyone else.

If your product does something hard or useful that you know how to do because you understand the audience or business, or includes data or knowledge that others may not know about or have, or just you can put the effort in to great service to build a large customer base it becomes harder to be copied.