Can we publish a Locator service without ArcGIS Server?
Assuming client don't have the ArcGIS Server in premise then create locator and GeoCode service
The short answer is no - https://doc.arcgis.com/en/arcgis-online/manage-data/create-locator.htm
However, you can submit updates to World Geocoder - https://support.esri.com/en-us/knowledge-base/how-to-provide-feedback-on-esri-basemaps-and-the-arcgi...
I can see their line of thinking on this in the hosted environment. Manage bursty computational resources like locators where everyone would want 3 of them. Serving tiles is pretty easy.
