A lot of people focus on a lot of things. They go wide, covering a variety of topics and specializations on the relative surface.
When you go wide, you volunteer away your opportunity to specialize. To focus. To master an area. To become known for something.
If you’re slightly versed about a lot of things, you’re not well versed at any thing.
Conversely, if you really focus, truly specialize, you allow yourself the chance to master your craft. You give yourself the opportunity to be THE practitioner that people think of when they need help in your chosen field. When you go deep, you can become far more successful.
So go deep, not wide.
The same principle applies for companies. What do you do that no one else does? Why should customer buy from you and not your competitor. In a world where unique selling points are getting more and more similar, great customer service becomes a key factor.