It's hard to sell a $500 ruggadised GPS unit when it's built into someones iPhone, and people are beginning to wonder why they are paying quite so much even for RTK systems when the actual HW is so cheap.
But if even small scale housing construction started could be persuaded to use the same 3D mapping/GPS technology that big civil engineering projects do then you could tie up a nice market.
From the prospective concept design of the street of houses, the planning permission filings with 3D height modelling, sight lines, light rights, the cad drawings, then the automated layout of roads and foundations with GPS equipped machines - all with an integrated Trimble system.
I do agree that the technology has become much cheaper over the last 10 years, while Trimble's pricing has not fallen at the same rate.
A Real Time Kinematic system can do mm (on a good day with a following wind) but they cost 20x as much!
My post wasn't totally clear - I meant people ALSO wonder why an RTK is $10,000 when you can build your own for a lot less (http://blog.makezine.com/2009/11/12/diy-real-time-kinematic-...)
I can see an established 3D CAD company really enhancing it as a potential bridge onto their bigger tools and providing more interoperability with other platforms. I can't justify buying a license of SolidWorks for my kid's PC but if SketchUp were a SW product with a ramp up to SW I would definitely consider it and even pay for it.
Time will tell.