To be successful, you need a product
The Internet Refrigerator is a meme that gets a lot of jeers, but I think at the core of those jeers is the fact that it seemed like a solution looking for a problem. To me, most of IoT feels like this (especially most of the stuff at CES).
Early devices like the toaster were done because they could be done. Dares and fun side projects. But they weren't real products that solved someone else's problems or filled a need.
I've seen a lot of kickstarters and startup companies go after home automation without really having a product or service that solved a real problem. And those have mostly faded away. The compelling reasons to use the products aren't there, leaving them as no more than novelties.
This is, perhaps, the genius of the Nest. It's a thermostat (boring), made to look beautiful (yes, a novelty), but with remote access, and the smarts to learn your schedule instead of you telling it your schedule. The goal is clear, the execution is beautiful, and now that they've had time to refine the results, everyone I know with one loves it.
I have an internet-enabled bathroom scale from Withings. Yes, really. What it offers is that it remembers my weight, every time I step on it. And it gives me that data later, graphed over time. And it does the same for my heart rate and some other health-related data. The problem it solves is that I hate data entry, which is why I never was very good at tracking my weight in the past. Now it's tracked for me, automatically. And now I have a handy reference for some of my vital stats.
These are useful products, even if still overly expensive and luxury items. But the electronics are just going to keep getting cheaper. But if the business proposition doesn't fill a need, just is "X plus the internet", I don't see it ever really being more than a novelty today, and tomorrow's humorous internet meme.