What are some ways to start a business in the age of self-publishing?

It's an honor to answer your question. There are many ways to start a self media business yah.

There are many self media platforms. Any platform can make money.

There are many ways to present self media. Gallery, graphic, video, audio, live streaming.

There are many ways to cash in on self media. Platform advertising share, reward, amateurs commission, content with goods, live reward, live selling goods. Buy products, buy services, buy courses.

Self-media way for physical stores to attract traffic, recruit guests. Drive the turnover of the physical store.

Ourself, like, good at, have the resources, seen, heard and thought, can be expressed. If someone looks at it, there is money in it.