The culture at Valve is pretty much crowdsourced. The handbook is a wiki. One of the first things we say to new hires is, 'You have to change something in the handbook.'
About half the people at Valve have run their own companies, so they always have the option not just to take a job at another game company, but to go start their own company. The question you always have to answer is, 'How are we making these people more valuable than they would be elsewhere?'
In order for innovation to happen, a bunch of things that aren't happening on closed platforms need to occur. Valve wouldn't exist today without the PC, or Epic, or Zynga, or Google. They all wouldn't have existed without the openness of the platform.
Everybody understands that you're supposed to say 'our employees are our most valuable asset' to the point where, even if it's really true, they're not going to really trust you until you've earned that - same with customers.
People who are constantly looking for the opportunity to do something new are also people who are not going to be helped by having job titles - job titles create expectations of specialization and focus which don't map really well to creating the best possible experience for your customers.
Traditional credentialing really doesn't have a lot of predictive value to if people will be successful.
