Small kids are a lot more work than many people realize. Ditto building a business. Trying to do both at once without being financially independent first is not a choice anyone should make if they can help it.

Building a business, particularly a consulting business, is pretty easy and doesn't take financial independence, especially if it's IT related. Incorporating is easy, you can do it online. Then call up ye olde consulting firms and have them find business for you until you build up a customer base that calls you directly when they need work done. Do this enough and soon you'll have so much work you'll have to farm it out to acquaintances (your first employees).

That is sometimes good advice for developers. But only sometimes — it's not work that interests mosts people.

For most careers, it's not very reasonable to quit a job and try to build a company.

Not everyone wants to build a business.