Ask HN: What's preventing us from achieving seamless video communication?

Ask HN: What's preventing us from achieving seamless video communication?
Better video compression? faster network speeds? alternative network protocols? With all due respect to all the amazing folks working in the domain, as a person working outside the field, the quality of even 1:1 video communication still seems far from ideal. Wanted to understand a bit what the main underlying hurdles are. Folks say there's less room for improvements with compression after H.264. I'm not sure how much network speeds are a factor given things can get botchy even with wired high bandwidth connections. The audio artifacts definitely impacts the perceived quality so not sure if there's room for improvement here technically.