Why do so few receivers include asynch usb; why do so many audio preamps not include hdmi?

What are your thoughts about this? Would you like to see this? For example, am pleased that Bryston includes HDMI on their new preamp, while Lumin is including HDMI on their new streamer (P1). What do you think?

I like the idea of more pre-amps (and integrated amps) including HDMI, especially supporting eARC. The asynch USB is a b
it harder to justify. I believe many of the USB ports on A/V receivers are not used compared to their HDMI or even optical ports. The buying profile of an A/V receiver shopper is most likely focused primarily on video, with a small percentage looking at other connection options. Roon customers tend to be outliers given how we connect to audio, video, networking, and different ports for connections. Plus, even with asynch USB becoming less expensive to implement, my guess is that only the higher-end A/V receivers and processors would probably include them based on cost targets.

I would prefer to see more eARC moving forward in 2-channel audio systems, less concerned about the USB

Including USB is cheaper than HDMI. HDMI 2.1 would potentially need video processing capability of up to 8K. Enhanced eARC is a fine idea but it comes with baggage pretty much useless outside of the AV arena!