In the latest issue of PC Gamer UK, Valve' s Erik Johnson and founder Gabe Newell explain why the company never went public. The key reasoning for not doing it, the duo said, is because it changes your customers. But the logical reason is that the creative process tends to get hijacked - or at the very least, heavily influenced - by the people that hold the most financial interest in a company.
The other reason, which neither talk about, is that Valve as a company decides where all that money goes; besides funding new projects, the company has the luxury of spending that hard earned cash on creative ideas, long-term support for products and investment into the most important aspect of a high profile development studio: the developers. Here's what both had to say about the subject - first Erik Johnson: