The performance of these binary protocols does not scale on most server implementations.
The protocol is not the bottleneck, the parallelism and memory latency is.
QUIC/UDP and BBR is mostly a way for Google to grab more than its fair share of bandwidth during congestion, and will lead to a tragedy of the commons where people using less pushy congestion control protocols like CUBIC will be edged away.
Care to elaborate?
Many providers limit or block UDP because of the history with DDOS attacks.