Ask HN: Startup-as-a-Service – is it real? Examples?

"Startups as a service" has been a niche subject for a couple of years, with varying meaning:

- outsourced innovation labs / "Skunkworks" for large corporations

- independent firms creating/testing ideas with hackathons etc.

- built-to-order startups and hiring/incorporation services for people/investors with ideas

I'm interested in the third form, i.e. the possibility to test an idea and secure its potential as a shareholder/investor while leaving details planning / early execution to specialized firms with experienced personnel.

Does this even exist? Does it work? Did any successful companies start out in this way?

What alternatives are there for individuals with the idea, financial background and experience but not the time / execution skill / network of potential co-founders to found a startup?