She was short of people inside the company who wanted to do the job. Of course you can always find people outside the company who want in (it's a job, after all). In the case of hiring people specifically for someone's project, presumably the hiring process has to act as a proxy for the 'is that project worth working on?' or inflexible resources (a machinist isn't going to work on Steam) get tied up in a project no-one else is interested in. Hiring the person as a temporary non-employee contractor would probably solve that, but I see how Valve's resource allocation system might make that difficult.

You never know when the machinist might have some interesting insight, especially in an organization lacking a machinist.

And they already had purchased over 100K of equipment, and yet nobody could use it since they couldn't hire someone who knew how to use the machinery - like a machinist.

Completely maddening if you ask me.

Which is why Valve has an economist, but not a machinist.

They had an economist - Yanis Varoufakis describes himself as "former economist-in-residence at Valve Software" now. Not sure when he left.