power cord length

There is no technical reason why it can't be as short as you like. But obviously it must be well constructed, so that it does not develop an internal short or open if stepped on, pulled, etc. And if it lacks UL approval, there could be a problem with your insurance if a fire ever originated as a result of overheating of either it or what it is powering.

why do companies not make a short cable?

Lack of demand, I suppose.

Regards,
-- Al

I have been trying to tell my wife for years ...Shorter is better!!!!!!!!

Signal Cable with make a PC any length you want.

Thorman;

My wife says it doesn't matter.

She's a liar.