Comment by modeless

Valve is focused on making a device that works well with their existing game catalog. It's a Steam device first, and it needs to be inexpensive to compete with Quest (which is subsidized by Meta), so they need to prioritize which features get included. I wouldn't be surprised to see a first party AR camera attachment a while after launch. The expansion port seems specifically designed for this, with the inclusion of MIPI CSI lanes for two cameras.