For many purposes they seem to have automated/script-based customer service that requires little manpower.

I reported a bug in their app in a review I left on the Play Store. Uber responded saying to report it on their website instead. I did so, they told me it wasn't valid because I didn't include screenshots. (Even though there was a clear description of repro and expected/observed behaviour). After a few days I got around to sending them screenshots, and received an auto-reply that the issue had been closed and my reply rejected.