I have done precisely that at times in the past.
....until I recognized I was enabling. She simply purchases more uncomfortable but stylish clothing that will likely be worn only once and then assigned a permanent place in the ever-expanding closest of unhappy fantasies.
I suppose I could try to view her purchase of such clothing the same way I do a meal at a fancy restaurant: a fleeting pleasure that's savored and then forgotten. But it strikes me as an extravagant and very temporary method of soothing her unhappiness.
Yikes!
Then my advice is to hire a stylist to take your wife "shopping" in your wife's own wardrobe. They'll weed out what looks good, what can be altered and what needs to go. They will also figure out HOW your wife should dress for different occasions to show off your wife's best assets.
This costs about $400 or $500, but is worth every penny for a woman with an over-stuffed wardrobe and nothing to wear. And it will save a LOT of money in the long run.
And if you have enough change leftover, hire the stylist for a few more hours to take your wife shopping at stores.
Your wife needs to see herself AS SHE IS NOW, and while I'm sure you give her plenty of reassurance, you aren't a stylist -- stylists are trained to teach people how to see and enhance their positive traits.