People who frequently travel to a bunch of different countries are a tiny niche market. The vast majority of ride sharing customers take few or zero international trips per year.

That isn't so much a network effect as it is burning money on 6 continents. If Uber isn't the most cost effective solution at home there isn't much incentive to use it abroad either.

I've been in lots of places - pre Uber - where I didn't even speak the local language. Even then finding a taxi was not taxing. If Uber can't make a profit on local traffic it is going to be a mighty feat if they make money off non-local traffic.

Doesn’t really match my experience at all visiting a city without Uber (Barcelona).

Driver took advantage of their complicated fare system to add supplement charges that didn’t apply: charged us the baggage supplement for our backpacks that we carried in the car, and charged us a supplement for going to the train station, which should only apply from the train station.

The local taxi authority requires us to complain by post with an original receipt.

The postage costs of sending that with tracking defeats the purpose.

Most people wouldn’t even realize they were overcharged, after all, we paid what was on the meter. And issuing receipts is only by request.

We don’t have enough data to determine if the driver was excellently skilled or suicidal.

Meanwhile with Uber, you get a fancy receipt emailed to you listing route/charges, a sensible (if unregulated) complaints process, and ratings from other riders.

I agree that they need to be profitable in order for this to matter. If they were, it would help with local traffic too as people would still prefer to only have one app installed. In my city there is a concurrent company that pays taxes locally and almost all of the drivers work for both Uber and them. I still sometimes order rides through Uber because of habit.

Network effect is more than none, but less than all.

Lyft is also around, and it seems that there is very little friction for both drivers and riders to choose/arbitrage.

I have had opposite experience in Japan