What a great case study. Successfully shifting 80% of mobile traffic to QUIC for a 50% reduction in latency is amazing. QUIC and the ongoing work with multipath TCP/QUIC will be huge QoL improvements for mobile networking.
The other awesome thing about QUIC is that it encrypts almost everything including header information, making middlebox traffic shaping worthless and demoting middleboxes in general.
It also makes hardware offloads like TSO and LRO impossible, and increases cost-per-byte served by a factor of 4 or more. So if you have infinite CPU to throw at QUIC and/or low bandwidth or connection targets, its great. If you are concerned at all about server-side efficiency, its terrible.
FWIW, I work on the Netflix CDN, and specialize in server-side efficiency; we have had 100G flash CDN nodes for years serving at 90G+ in production. None of that would be possible with QUIC as it stands. I suspect our max B/W on these machines would drop from ~95Gb/s to 20Gb/s or less if we were to switch to QUIC.
Don't blame QUIC. Blame ISPs and middlebox makers for abusing their (literal network-wise) position and breaking the end-to-end principle. History has shown that we just have to encrypt everything and quite literally cut out the middleman/box.
