I am thinking back to the days of Spectra Precision (bought by Trimble) and the lasers they sold to farmers and construction way back when.  Then the work Mark Williams did with total stations (a local version of 3D GPS) to get that right which let him be early with GPS vertical control followed by Trimble.

Yes there is a bigger market to sell into today but GPS signal source is not the same laser signal source and it is important to keep that in mind when you consider the later players into the market.

Arnie