Alright, let's put on our engineering caps. To have a wireless connection, we need:
- Wires connecting the subsystem to the wireless transmitter
- Wires connecting the transmitter to the power supply
- An internal environment that's fairly well shielded against RF, but allows wireless signals in its volume
- Wires connecting the receiver to the element the subsystem is trying to communicate with
- Wires connecting the receiver to the power supply
And this is just for one-way communication between a single set of systems.
On the other hand, for wired communication, we need:
In the grand scheme of things, wired connections (Over the short distances inside a vehicle, anyway) are simpler, cheaper, more reliable, and lighter. Going wireless would add huge amounts of cost, complexity, mass, and potential failure points - all of which space programs like to avoid if possible.