This article misses what I think the sweet spot is for QUIC which is for use over the last mile for mobile devices. Cellular and wifi can be spotty. QUIC is designed to be able to recover lost packets and not interrupt streams unaffected by the packet loss. A QUIC connection can be migrated between networks and continue streams without each needing to be re-established. So if you loose wifi and switch to cellular, the existing requests will transition and continue.
So far traffic is better handled over http 1.1/2 than QUIC, but if a CDN is at the network edge, then it can use http/3 to the end users, but backhaul over http/1.1. This is why Akamai and Cloudflare are at the forefront of QUIC deployments. Most routing equipment has been optimized for TCP not UDP, so it will take a while for QUIC to catch up in terms of throughput and latency compared to 1.1.