Why a Thunderbolt Display can’t power a new Thunderbolt 3 MacBook or MacBook Pro

Steve Dvorak writes in with a question about the 27-inch Apple Thunderbolt Display and the new MacBook Pro.
While I can do the Thunderbolt 3 to 2 adapter for video and Thunderbolt accessories, I can’t use the power that comes from the display. There appears to be no adapter created that provides power from MagSafe 1/2 connectors to USB-C. Am I missing something?
Unfortunately not. The USB-C port(s) found in the 2015 and later MacBook and 2016 and later MacBook Pro models can pass power bid