I'm aware of that. However there are obfuscation software e.g shadowsocks that wraps wireguard or any other connection.
Unless you mean WireGuard over Shadowsocks UDP transport, but that is even less common.
(Disclaimer: I wrote the official Go port of Shadowsocks https://github.com/shadowsocks/go-shadowsocks2)
Sometimes a bad solution is better than no solution at all.
Tunneling WG over SS would be inefficient for obvious reasons. Maybe there should be a more lightweight solution.