Let's talk power cords

OSHA?

Occupational Safety and Health Administration.
Between them and UL and also national electrical codes, essentially solid core power cords are illegal. So if one makes a fire, electrical hazard or any such, it won't be covered by homeowner's or renter's insurance.

Oh, jeez...

And there it is in a nutshell. The only ones selling power cords made of Romex are the ones that are either ignorant of electrical code or have simply elected to stare down the shotgun barrels.
As a manufacturer, I follow the code because I don't want the liability. And that is why most power cords are flexible, because the people that make them like to sleep at night.

If you think that jump on lamp cord and pretend it sounds good.