Chance of nice pension and a job for life = Check (not so much for a failed startup)

I am not saying one is right or wrong; the pension could "poof" go away with legislation for example. However, I will say there are compromises/choices to be made. I am quite indifferent to the matter as we all choose a path... The difference lies in how much we think we control vs. how much we actually control.

Chances of a nice pension and a job for life are pretty low in academia these days.

A quick back of the envelope calculation of the value of a $150000 salary over 30 years is 2-4 million (depending on what you assume as your interest rate).

What are the chances that a person doing a startup will leave the startup with 2-4 million dollars? How does it compare with the chances of getting tenure at a university that pays $150000 on average?

I would disagree. Just read the list of nobel prize winners and how many of them are academics. These are often actual paradigm shifts in how you think of the world that lasts generations, not decades.

Compare this with the impact a successful startup has and it does not quite compare. A successful startup creates new jobs. Novel science that can be applied creates entire industries.

When he/she says high returns I'd imagine he/she is referring to monetary gains.

So impact withstanding, a Nobel prize winner is awarded roughly 8 million SEK, which is 941320 U.S. dollars. Now, disregard their monthly salaries, as the time it takes from winning a Nobel Prize varies from an infinity to once or twice and consider the portion of Nobel prize winners compared to the number of scientists and measure that against the number of businesses owners that rake in 941320 dollars a year out of all of the business owners that there are and I'm sure you'd agree that if you are optimising for personal economic gains going the academic route is not the wisest choice.

Yeah, working in academia, with its endless proposals and grant applications, is a bit like running a start-up that never succeeds.