The power law part is why the contribution of the other 99 percent of outcomes to the expected value is close to 0.
If, for example, the distribution of outcomes was uniform between 0 and 100 billion, the startup would be worth 50 billion. Because the distribution roughly follows a power law, 1 billion is a better estimate.
The salaries he listed were for executives, not coders.
If you pay your CEO too much more than $260k, there might be a risk that he/she start worrying about keeping the job (and the high salary) more than growing the company.
The main point of the story that the OP was highly valued by Zynga, but he left anyway. It details his rapid access to key people and that his old boss begged him to stay (multiple hour convo at boss' house).
It's sort of like saying your old girlfriend was super into you, and begged you to stay with her, but you left her anyway. Most people might agree that making a public declaration of this would not be doing her any favors.
A reasonable person could consider this post unprofessional. Zygna (whatever your personal opinion of the company) was singing his paychecks and could be considered to deserve the sort of respect many people give former employers in public.
In all seriousness, congratulations pg. You've played your cards very well the past 10 years.