It's really important that businesses sell and market to a niche. If you try and sell everything to everybody, you successfully sell nothing to anybody.
People are only really interested in you solving their specific problem, when they are ready to have it solved for them, so when they have a compelling need.
You want to get people to think "they really understand MY problem and know how to solve it", and this is something you can't achieve if you are trying to solve everyone's problems
If you focus on a niche, then you have got far more chances of being successful in selling.