OSM is big enough and good enough that all the tech giants (except Google) would do better to start with OSM and improve it to meet their needs than to start a new, completely proprietary map from scratch.
That means that we are in an amazing place where in addition to the substantial volunteer OSM community, there are contributions from Amazon, Apple, Facebook, and hundreds or thousands of smaller companies all coming back in to a single global map that everyone can use. It's very worth it to do work that strengthens OSM, as it increases the number of companies that will use it, and possibly contribute back, rather than doing work the world at large won't benefit from.
P.S. As a disclaimer, I am co-founder of Geocode Earth (https://geocode.earth) a small business that does indeed profit from OSM (and other open) data. We also contribute back both through OSM contributions and by releasing our core software as the Pelias geocoder (https://pelias.io)