Then they joined a not-gonna-happen startup (to do with optical fibers) as a CEO, investing something like $50k of their own money to get the position, later increasing their stake to $150k. If the startup is about to die this is not very hard. They had a plan to turn things around and in at least one case (out of 4-5 tries) it worked. This guy was then forced out of the CEO job, but he was certainly very well compensated for his efforts (triple digit millions).
Of course he did try that 5 times, and lost everything 4 times out of 5. Including years of work. It's not for the faint of heart.
The other one made out well as well on one of his past efforts that was taken over by a competitor for a very nice price, after which he left. He's now working on a company that I'm not really holding out much hope for.
Why is Alcatell-Lucent kinda pointless?
If you want your entire career to be exactly like, let's say, the first year of your master study at university, with exactly defined problems to be solved, then get a thank you, maybe a nice compliment if you've done exceptionally well, then to see your solution disappear and never even be used anywhere (and certainly not voluntarily by a customer) or if your family has enough money to build a house out of 100 dollar bill bricks, it's the perfect place. A place where people use extreme social pressure, even crimes, to get the slightest of advances within the company, because there is no future there. I would make damn sure all my interests lie outside of work though, even in that case.
I also don't think you should try and exclusively maximize your dollar earnings in your 20's, personally. But it's just an opinion.
You might learn a lot by jumping into a startup, but your chances of failing are probably higher than if you start one 20 years into your career. The average age of successful startup founders is not in the 20s.