You can usually disable it completely in the BIOS, and it won't be drawing power if it isn't doing anything. I can get wanting to not pay extra, but realistically supporting an extra custom hardware configuration probably costs more than they would save on the part.
> The issue is that on some machines, the video-out ports go through the dGPU. Does that still work if the card is disabled in the BIOS?
Traditionally yes; the machine is designed to only run the dGPU under heavy load, not all the time, the BIOS setting just disables doing the thing that you did in the "heavy load" condition. I guess there might be machines it wouldn't work on but I've never known any.
