Wireless has a lot of stuff going on.
Layer 1 off wireless is split in many different levels.
This, combined with the fact that interoperability is paramount, but there are only a few providers make for complicated standards. The interop between a few providers problems means the standards have to bow to actual usage a lot more.
This applies a lot more to 3gpp (cellular) stuff than WiFi though. Especially because 3gpp is commercial only, is a lot more 'trust the network', and cares about billing. Moreover, the interop is meant to give a pretty seamless roaming ability, whereas e.g. 802.3 is only about working on a single subnet.
Moreover with WiFi, which partially uses time-division (like ethernet) you cannot have two devices sending at the same time. However, unlike old-style shared medium Ethernet, you can have two devices outside of range of each-other, but both reaching your WiFi router. This means the transmissions scramble each other at the router, but the devices can't detect this.
Hence, you cannot do CSMA/CD (collision detection) but need CSMA/CA (collision avoidance). This means you get ACK messages at layer 1 of your protocol.
In general, it might be the Multiple Access model that makes wireless hard.