Also Valve has always been a private company tightly controlled by insiders, whereas Sierra had already been a public company since 1989, subsequently acquired by CUC in 1996 for $1.5bn, and embarked on a non-stop acquisition spree in pursuit of short-term growth, which usually ends badly (think Gateway, AOL, Time-Warner, etc). Esp. pre-Sarbanes-Oxley.

Moreover, Gabe Newell always had a controlling stake in Valve ever since 1996, so that prevents any shenanigans. There are comparatively few shareholders (than a public company) and they were all long-term, since Valve will likely never go public, certainly no year soon, or even be privately acquired; while Newell controls it.

In this instance your complaint is about corporate governance rather than tech; (how far back did tech people stop being in control at Sierra?)