Shapely was around long before Mapbox, and Rasterio too. Both are based on stalwarts of the open source geospatial world - GEOS and GDAL.
Vector tiles, Mapbox GL, and Mapbox styling, and numerous other libraries however did grow out of Mapbox - the amount of geospatial developer talent they hoovered up must have made it pretty amazing to work at for a time.
Vector tiles, Mapbox GL, and Mapbox styling, and numerous other libraries however did grow out of Mapbox - the amount of geospatial developer talent they hoovered up must have made it pretty amazing to work at for a time.