Serial Vs. Parallel data transmission

[Number2Pencil]

Homework Statement

Why is serial data transmission preferred over parallel transmission when needing to transmit data over vast distances?

Homework Equations

The Attempt at a Solution

I think this has many different reasons...but I'm trying to pinpoint important ones.
-I think the most obvious is that a parallel transmission needs more lines and thus cost more.
-Another one would be cross-talk is more emminent with signals bundled close together.
-(I'm not sure about this one) but isn't most serial schemes asynchronous while parallel is usually synchronous? a clocking signal could get tainted with noise or DC drift.

Can you help me think of any other reasons?

 

[wildman]

I would stick with the first reason you gave. Cost is the important reason.