They've already got a caste system, actually. If Valve hires you to do customer support, the only thing you can ever do at Valve is customer support. They don't allow sideways-promotion from their support department like many game companies do with QA/support staff because they don't want there to be a 'back door' into the company.
I began to write about Toyota and Admiral Rickover's "Nuclear Navy" cultures, but then stopped.
I'm not sure if cultures like Toyota or the Nuclear Navy can be considered under this heading, as they mostly worked at a procedural-improvement level, rather than a product-improvement level.
The only thing that works is deliberately cultivating a culture where driving out the old bads is as important as creating the new goods.
Put another way: for self-direction to work, the culture needs to rank improvements as highly as novelty. Possibly higher.