Switching over all uses of TCP to QUIC will go even slower than the IPv6 migration. TCP works for most things and is trivial to use so it will continue to get

Switching over all uses of TCP to QUIC will go even slower than the IPv6 migration. TCP works for most things and is trivial to use so it will continue to get use. But unlike IPv6 there's few barriers to adoption of QUIC where it really pays, so I expect that QUIC will be adopted by a lot of applications pretty quickly.