Hey /u/dbburnerthrow ! It sounds like you and your wife need to have an honest sit down with the closest family members. It sucks to feel the way she does, but she doesn't need HER family to be insulting her about it. Maybe it's not direct insults, but wow, I would cry (definitely at some point) if my life had been hers for 15 years. My fault or not, having an unsympathetic family for that long is really rough on your confidence, and probably doesn't make her want to get anybody a nice gift anyway when they can't appreciate her trying (especially if they "know her so well").

Have you tried sitting down, parents, wife and you; explicitly saying how this is hurting her? You are so right to want the lies to stop. You shouldn't have to do that. And your wife's shortcomings at Christmas aren't that funny, especially if she knows them. Let's not discuss how she doesn't want to change, that will be her problem when she realizes it's the only way to have her family treat her better, and you know it's true to a degree too.
I think you may be right to return the gifts you already bought (not sure though, your call obviously). But it's worth maybe doing some cards with your wife. Take some time and prompt her on what she likes about her family members, or nice memories she has, get her to give or just recount those things at the family gathering. Admittedly this is hokey, but eh, try it if you will. Sometimes people need a break from material stuff. You could also do charity donations from the family, not sure if you could do PLAN Canada, but they have cool gifts. And it's not your idea, it's mine!

Reddit is weird, and you're just trying to be a compassionate husband to your wife and family. You don't need to give them such good gifts, just keep trying to help her figure out how to do it. Even the Grinch's heart grew, after all.