Re: "All of its premium data"
A US startup inventing a product that needs route mapping eg. Uber, Mapquest etc can get all the data for free. They then get bought by a Google/Microsoft/etc who can afford to just do their own UK mapping.
A British startup is caught between the expense and complex licensing terms of OS data or Postal Address File so never gets the chance to make it to market.
It's the same way that free local phone calls in the USA launched the bulletin board and then consumer internet there while the UK had expensive per/minute billing and restricted set of expensive BT approved slow modems.