Different content has different audiences. When we grow bigger, if you stick to a specific niche (that you're good at and love) the audience will follow and you will grow a very big fan base that will help get exposure far easier in the future. Even if that niche isn't that big as of writing.

Heidi for example has dominated the travel niche, that's all she posts about.
Cryptooctupus is the data and outreach dude.

And many more I just cant remember ATM, but the basis is the same.