Bit of a stretch to call that a "charging cable." Their 240W rated 2 meter USB-C charging cable is $30 https://www.apple.com/shop/product/MU2G3AM/A/

But if you're interested in why the Thunderbolt cable costs more than charging cables, some folks put one through a CT scanner recently:

https://www.youtube.com/watch?v=AD5aAd8Oy84

That's fair, as it does more than just charge.

Let's take another example from Apple:

https://www.apple.com/shop/product/MWUG2LL/A/pro-stand

In a similar vein, the $700 Mac Pro wheels kit

I hear they roll very smoothly, and since they don't have brakes you may need to re-level your floor to keep the computer from rolling away