How to Become a Go-To Person?

Some context: I am in the process of constructing a house. Recently, I contacted a lot of people in areas such as mortgage loan, building contractors, architects. To my surprise, hardly anyone followed up. That implies, they must be getting a lot of work. We could say the same for doctors, lawyers etc.

One the other hand, if we look at the software industry, everyone is replaceable no matter how good they are. So how does one become a go-to person?. Not necessarily at work. But outside of work too, so that one doesn't have to depend on the employer. I know that having skills in niche areas will help. But then, there will always be a dependency on the employer. Also, the entry barrier is very low in tech. Anyone could learn any technology.