Comment by earthboundkid

I think the point is just that for most applications, the reverse proxy server is not a performance bottleneck, so it doesn't matter for any practical purpose. Caddy could be twice as fast or slow and it would not change the number of servers you need to deploy one way or another. If your reverse proxy is a bottleneck, you'll know and probably have the resources to build something custom instead of using Caddy or whatever.