[mytailorisrich]

Wifi's use case was, and still largely is, to be a wireless LAN. This means few users, no mobility, static devices, short distances, devices plugged in (not so true now). It started pretty much as exactly that: Just transmit ethernet frames over the radio and everything else is exactly as wired ethernet.

Cellular standards cater for a very different use case and, as a result, as vastly more complex and robust. To manage a lot of moving users and to support mobility is hard, also taking into account that cellular has had to deal with quality of service from the beginning because even if data rate was low voice requires a constant throughput with constrained delays.