They can't subsidize a Steam Machine like a typical console manufacturer, because a significant portion of their userbase already owns games on the platform. How many additional sales are going to be generated by Steam Machines? I see it, and likely Valve sees it as another place to play your existing Steam Library.
I'm not sure they will sell console numbers, I don't see a significant amount of additional game sales, and Valve also has to take into account uncertainties around inflation of PC components (this AI craze is only causing more issues), and they need to plan a price point in advance to maintain a price point now and into the future unless they want bad press for raising prices every few years for largely the same components.
It makes perfect sense why Valve has not announced a price but is warning us to expect it to be like a PC rather than console. As a consumer, I don't like this, but I understand why it is happening.