Successful startups solve real problems. If you never have a job you won't see any problems apart from the ones that affect you directly as a consumer, or later as a business owner. For example, there are a handful of startups in the container shipping industry at the moment that are really disrupting that space. Could anyone who hadn't worked in that industry first have identified the problems and seen the potential to solve them? No. You need experience of the industry to see what's wrong with it.

Having a job before doing a startup isn't about learning some skills that apply universally. It's more specific than that. To that end, if you have ideas for more consumer oriented businesses that you can build without industry knowledge, there's no need to get a job first.

One small caveat: having a job and being an employee means you'll understand what your own employees feel if your business grows to the point of having any. That would be useful.

These are all very good points.

"having a job and being an employee means you'll understand what your own employees feel if your business grows to the point of having any"

It's more than just knowing how employees feel, it's knowing what employees do (e.g., what's the role of a CTO, a product manager, a marketing person, etc.?) and how to manage them. If you've never been an employee or a manager, how likely is it that you'll be a competent CEO who can hire effective employees and managers? If a company ever becomes successful, it won't be just a couple of programmers in a room anymore.

I'd also add that the more experience you've had in the business world before starting a business (and the more you've seen of life in general), the more likely it is that you'll be able to recognize bullshit - it will be harder for potential co-founders or investors to take advantage of you.

If it's a really complex industry (especially ones that have a lot of regulation, such as energy or healthcare) I think it's a good idea to work in the industry for a little while - just enough to understand what the different areas are you need to know about. It'll probably be a faster learning curve to spend 1-3 years as an insider than wandering in the wilderness there.

If it's more consumer, or you have a clear way to build revenue early, just go for it.

Either way, I think being in a big company (or more established startup) to learn culture, work with smart colleagues, etc. is definitely a nice-to-have, but not a must. You can pick that up on your own as you build your own startup. Good luck!