Because you have an Auxiliary light ON. It does not render, but it kills most shadows in viewport for better viewing. That is what it's for.
You have to balance your lights and shadows in the scene with Auxiliary light OFF.
Thank you. I thought it might be that, but I can't figure out how to get any light to shine on HER like that. I've tried adding a light, but I don't know how to actually make them shine, and usually when I add them they're so far away from the character that they're almost impossible to move close enough to them to matter. I tried resetting the movement numbers at X, Y, and Z, to match the character's, but they never actually go to the character. I'm SURE there's an easier way to get props and lights closer to the character, but I have no idea what it is.
I think they should at least have an automatic light you can turn on that emulates the axillary light with its settings, for those who like how it looks... and who are apparently morons. Oi.