There's a few reasons: 1. WiFi is largely unmanaged so all the clients basically act like they're on an Ethernet hub. If they detect a signal they wait a rando

There's a few reasons: 1. WiFi is largely unmanaged so all the clients basically act like they're on an Ethernet hub. If they detect a signal they wait a random period before trying to send again. 2. Besides interference from nodes on the same network, you're getting interference from other networks on the same channel. Your WAP and WiFi card ignore those networks logically but they still need to yell at each other over the noise. This makes for dropped frames that need to be retransmitted. 3. WiFi is using unlicensed bands and has very low radiated power limits. The 2.4GHz and 5GHz bands in particular don't propagate well. This keeps a neighborhood of networks from making the spectrum totally unusable. Even still areas dense with WiFi networks make for really shitty interference. Cellular on the other hand is aggressively managed. For one handsets and towers transmit on different channels. Your upstream won't affect my downstream. Besides every channel being multiplexed a tower can tell a handset to change channels or even entire bands in order to managed congestion.