Earlier quoted context omitted.
Working as an employee is not without risk. There is the risk that you'll invest 10% or 50% of your productive lifespan in an employer who squanders it all and leaves you jobless without notice instead of an employer who puts your abilities to good use and recognizes the value that you create. The risk is partially mitigated by receiving a paycheck during those wasted years regardless of the employer's competence.
And software developers are different from literally any other kind of employee in this regard... how?
If there was a big shortage of say people with business skills, then they'd be worth more, or sales. Good sales and biz dev is always valuable. But there's not really a shortage of them, in the same way that there is in software.
To give an example, I worked at a startup. We had millions to pay salaries. We were paying 150-200k in salary. We couldn't ever grow over 5. We wanted to hire about 20 more. We had plents of designers, office managers, and leaders. Devs were far more valuable than a new hire in those other areas, because we were short. I left after a while, we couldn't ever hire anyone to work on a group I was supposed to lead.