In my experience (author of "technical" book about digital strategy), you need publishers for two things: 1) there's still some kudos in having something commissioned, edited and published by a known entity and 2) the imposition of a hard deadline.

If you can cope on your own without either of these, sure, self publish.

It is a hard slog, and as others say here, it's unlikely to earn you a reasonable wage - but it's hugely satisfying to see it through knowing how much discipline it takes.