Why does them being private make what they have done impressive?
Heck, Microsoft followed exactly the same trajectory some years earlier, to the extent that their operating system is still synonymous with the idea of a desktop PC outside of the US (which I understand leans heavily towards the Mac, somehow). Their position is showing signs of crumbling only after multiple years of neglect and outright self-damage to their OS. The stability of a monopolist position locked in early is sometimes greatly understated.
They do have money. They made tons from Half-Life etc. Then they now have a huge continual income stream from Steam.