We are in a strange world today because our MTU was decided for 10mbps ethernet (MTU/bandwidth on a hub controls latency). The world is strange because 10mbps is still common for end-user network connections, while 10gbps is common for servers, and a goodly number of consumers have 1gbps.

The range means MTU varies from reasonable, where you can argue that an IW of anything from 1-30 packets is good, to a world where the MTU is ridiculously small and the IW is similarly absurd.

We would probably be better off if consumers on >1gbps links got higher MTUs, then an IW of 10-30 could be reasonable everywhere. MTU inside cloud providers is higher (AWS uses 9001), so it is very possible.