The reason thieves steal cables and wires is because they sell it at scrap metal yards for money.
Some thieves will steal cables and wires especially the copper wires and cables for high scrap value to help with purchasing of their meth and other drugs.
Many thieves who do steal cables and wires, air conditioners etc are drug dealers or those who want to just buy drugs.
However some people steal cables and wires and air conditioners, brass and anything else they can sell just because they want to steal.
Copper for scrap when clean sells for over $3.00 a lb right now and so it can make them some decent money.
However once stolen the scrap wire costs the owner more money than what the thieve made from the scrap copper.
When scrap copper was really high a lot more copper and even air conditioners were being stolen and sold off.
This made it so that now scrap yards have to get the vehicles tag number, drivers license, ID and sometimes picture of the seller and the scrap and have the seller sign a paper.
It has slowed down copper and wire theft but still copper wire and other wires and high value materials are still being stolen.