[illuminate]

"We should assume that bigger pipes cost more money"

Why? The cost for running the fiber has already been paid.

"Cable seems to have no problem bringing movies through the old copper wires."

What companies choose to charge for old copper is irrelevant to how much of a profit one can make off of newer cable drops.

[Alaskan005]

"Why? The cost for running the fiber has already been paid."

Not every mile is owned by one company, the internet is a series of tubes

[illuminate]

This is true! However costs over the years have plummeted for those uplinks and the reduction in costs have not been passed on to the consumer through much lower priced service.