Everyone has rightly pointed out that the cost of this sort of device is inflated by regulatory headaches and liability concerns. Let's not forget simple economies of scale here. A video game controller will likely sell millions if not tens of millions of units before it's eventually retired from the market. A medical balance board, on the other hand, is at best a niche device whose sales will likely be at least an order of magnitude (or two!) smaller. The costs of designing, testing and building this device are borne by a comparatively tiny number of sales, hence the higher price.
This is a real-life example of how the Android permission model is pretty well thought-out. Any time you install an app from the Market, you're presented with a list of all the hardware and software resources that it utilizes. Installing a tip calculator? When you see that it needs permission to read/write contact data, access your location and have full internet access, some giant red flags should go up. True, you can't tell what exactly the app is actually doing with those powers you've granted it, but it definitely helps highlight potential shenanigans. An Android-style system could have helped identify this app as a potential privacy risk. What, exactly, does a real-time traffic app need my contact info for?