Proximity and micro-switches show position. Speed sensors do exactly as the name says..... output a rotational speed.
On a gear assembly there are wheel speed sensors for Auto-Bakes/Anti-Skid, brake temp sensors, gear tilt sensors (if four or more tires per gear), brake fans (if equipped), squat switches (for weight on wheels), and gear position switches (either micro or proximity).
Not all gear have every item listed above, but you can understand the amount of wiring to support all these.
You're comparing apples to oranges as far as functions go. Each item has its own use. Each item has its own wires.