Part of this resurgence can undoubtedly be explained by the ready availability of high quality open geospatial data sources like OpenStreetMap.

The United States has always had a lot of open geospatial data available, but it's patchy, can be hard to find, and is of wildly varying quality. In Europe, open (geospatial) data has become the norm, but that wasn't the case even 10 years ago. And in spite of harmonization efforts, it can still be hard to cobble together map data that is consistent across countries from government sources.