Of course you can!

But it's harder because you likely will have a bigger number to reach before 'ramen profitability'.

Cut your fixed monthly costs as much as you can as soon as you can, that will increase your runway considerably.

A step back is always hard, but this will increase your chances of success by quite a substantial margin.

Why not?

The question is how much you have in the way of savings, and what sort of lifestyle you want, and how quickly the startup would either 1) fail, so you can get on with your life or 2) start generating money.

Hmmm...

if it were me, it would mostly depend on how I want my life to be 5 from now or 10 years from now. (or in which direction i want it to be going)

And then choose whichever option has a higher chance of delivering that. So do you know what you want 5 years from now?

Also, it would partly depend on whats important right now? high excitement, high reward, high risk type of position or a safe comfy type of position?

Good luck.

The most important thing for the next 5-10 years to me is a) be happy b) provide for my family (I do have two kids and a stable marriage). All my jobs until now were very good, but I was hardly happy at them. I worked at big, big name companies in tech and also in one start-up, albeit not as partner.

Maybe you should start out with part-time 'regular' work, and do your start-up stuff on the side, then as you make more money on the side you can build down your 'regular' work. That way you get to do it without taking the plunge in an all-or-nothing fashion.

What's the best way to find that kind of work?

Anything will do, really the only requirement is that you don't have to be there all the time, so this is more geared towards the kind of job where people can be replaced on short notice without interrupting the workflow.

Think retail, that sort of thing. All you need is for it to cover the basic expenses and to leave your head free so you can think about stuff while doing the work. Then when you get home you're not too mentally tired to do some 'real' work for a bit, and on your 'off' days you can implement the stuff that you've been thinking about / working on on a slightly larger scale.

When I was 17 or so I worked in the mail room of a bank while at the same time working hard on becoming a professional computer programmer. If the work had been more demanding mentally that would have been a lot harder.

You can go start-up but you can also go start-down. When you are very young you weight failure with a low number, when you are over 40 and have a family to support failure is a big factor. So think in this equation:

What-to-do = maximize w1p(failure)+w2p(safety)+w2*p(success), where wi are personal and family factors, and p are probabilities.

Is your experience something that a start-up need? or is experience only something to change for the future?

I think you might be too wise and experienced for that </sarcasm>