They prioritized cost, so they omitted eye tracking hardware. They've also bet more on standalone apps rather than streaming from a PC. These are reasonable tradeoffs. The next Quest may add eye tracking, who knows. Quest Pro had it but was discontinued for being too expensive.

We'll have to wait on pricing for Steam Frame, but I don't expect them to match Meta's subsidies, so I'm betting on this being more expensive than Quest. I also think that streaming from a gaming PC will remain more of a niche thing despite Valve's focus on it here, and people will find a lot of use for the x86/Windows emulation feature to play games from their Steam library directly on the headset.