The business model that worked for Coach was: high-quality long-wearing leather goods, mid-range price point, iconic features (turnlock, stitching, hangtag). The Coach bag didn't have to scream "Coach"; like an Hermes, you knew it when you saw it. But, unlike Hermes, Coach was and is an aspirational brand that consumers could and can aspire to.
Over the years, Coach strayed from its successful business model. Coach flooded the market with affordable signature bags. Everyone has one, the bags scream "Coach", you don't look at the bag and think "nice bag, where'd she get it", and search for the more subtle iconic features of luxury bags. You think, "everyone has that."
When the market is saturated, a product is no longer a luxury item. And the brand is no longer an aspirational brand. Pretty simple.
As for some of Coach's competitors that are mentioned in this thread, I'm not impressed ... yet. The only reason a Michael Kors bag has ever caught my eye is because of its incredibly large hangtag or because it is a signature bag. In other words, the bag is screaming "Michael Kors", not saying "I'm a beautiful bag." Kate Spade bags have only been around since 1993. And, talk about unexciting? Some of them look like I stitched together a few pieces of leather on my sewing machine. Yes, they're that unshapely. Trendy, maybe. But not beautiful bags. As for staying power, we'll see if either of these designer's bags have the staying power to sell as "vintage". Oh, and when you do want to sell that vintage bag, how are you going to authenticate it?
I'll stick with Coach for now.
Good luck, Coach. Your signature items are what are selling in overseas markets. They're also what is undermining your brand in the US. Figure it out. You're an attainable aspirational brand. Make it work.