@ Pete (unrelated) you used to be able to pick up the GE wireless devices at the big box stores. Think the orange and blue home improvement stores sold them back in the day, not sure about the electronics vendors. They really started disappearing after the GE/UTC business deal. Some were the same, others were compatible but used alkaline batteries.
The largest reason why you're not seeing compatible or trade style devices in the retail stores as it's not in the manufacturer's best interest. They have their own distribution model and it would erode the sales of their distributorships and the trade market......and then it would become an issue for dealers to determine what devices they installed under contract vs. the end user.....which would probably lead to legislation in the industry to move the alarm and security market to be just like the UK. Lock people out of panels, tamper everything, password protect and other physical security measures, including requiring T&I clauses on systems and require certain grading to even be monitored. It's kinda good for the industry, but bad for end users and some of the "engineers" take themselves too seriously.
Also, as far as Zwave and UL, it only covers security, not fire alarm, which is going to be a stumbling point. The rest, like battery life and range could most likely be addressed in time.