Off the top of my head, there are a number of companies/services that can serve as alternatives to Google Maps, and one way or another they all contribute to the collective quality of open source and open data map tools:
* geocode.earth (https://geocode.earth) has geocoding including autocomplete based on Pelias(https://github.com/pelias/pelias)
* Interline can help with routing, OSM extracts, and transit data(https://interline.io)
* Stadia Maps also offers map tiles and routing (https://stadiamaps.com/)
* GraphHopper (https://www.graphhopper.com/) offers routing and geocoding
* OpenCage (https://opencagedata.com/) offers geocoding based mainly on Nominatim but also a bunch of other geocoders
* Jawg.io (https://www.jawg.io/en/) offers maps, routing, and geocoding
Roughly speaking, open data allows for lower prices because investing directly in gathering proprietary data is super expensive. Open data coverage is getting pretty good in lots of areas, and is better than proprietary data in a lot of developing cities (like Jakarta). It can often be updated much more quickly. Google is notorious for taking a long time to fix errors.
Likewise open source map tools are definitely behind Google in many respects, but there's the advantage of transparency and ease of migration if one particular provider happens to go away, or customization is needed.
I'm sure I'm missing some services, and am happy to talk more about any of the challenges/features as much as I know.
Disclosures: I am a co-founder of geocode.earth, and a former employee of Mapzen, along with the founders of Interline