If they had a lump sum donation of $100M, they could probably safely expect a return of 5% per year on average (many years could be worse).
As long as their costs are less than $5M per year, they can effectively run forever, barring any long-lasting financial depressions (the likes of which we've never seen), or severe financial mismanagement.
This is how many museums and universities operate, and what the above commenter was referring to. :)
Okay but museums and universities also rely heavily on ongoing donations. A 5% annual yield is far from a guarantee. Not to mention that running a tech company is very different than running a museum or local symphony. A tech company has to attract and retain top talent that is very expensive and costs scale with adoption.
As long as their costs are less than $5M per year, they can effectively run forever, barring any long-lasting financial depressions (the likes of which we've never seen), or severe financial mismanagement.
This is how many museums and universities operate, and what the above commenter was referring to. :)