It is too early to declare DLNA a failure, but I would not be surprised to see them fizzle. In my mind, the problem is with the channel. You can not start out with something this complicate by going retail, selling to the guy and gal who could barely program their VCR. You need to start this sort of thing by selling to the professional home network installer.
The professional installer is trained on systems, skilled at workarounds, technical and they will find the products that work together and only use those products. They do not randomly go to Wal-Mart and pick up a Colby this to work with an Apex that. Retail is an interoperability nightmare for anything complicated. Installers find what works and stick with it as much as they can.
Once they install a system, their customer is asking for a service call if they tinker with it. This is totally different than a system the customer buys at the store and installs by themselves. The silver bullet for HD home networking is to go through a professional until you know what you are doing. Then enter retail with a few products and grow the market from there. DLNA tried to rush into retail with dozens of products from dozens of companies. You just can not test for everything that will happen once the product leaves the store.