While network latency affects all network communications, it has minimal impact on dns services.
First, most dns queries and answers use udp as the underlying network protocol. The query and answer are each contained in a single udp packet. And, unlike tcp, there is no tcp handshake.
Second, dns lookups form a very small part of most user sessions. The impact of latency is buried by the sheer weight of other network traffic.
Third, in most cases, network latency effects are hidden by the workings of dns caches. Also remember that dns lookups are also cached by the client.