Calling has absolutely not the same friction as using an app. It's orders of magnitudes less efficient, more expensive and sometimes just impossible (good luck calling radio taxi in some countries where you don't speak the language). I think comparing what we could do 20+ years ago with what we can do now and saying "meh" is outright absurd. But, hey, everyone is entitled to their opinion.
Not to mention the experience of calling a cab as a foreigner and having the driver take advantage of you by price gouging you or taking you on unnecessary detours.
You might be overestimating the gap in efficiency. For example, last night, I ordered a pizza for pick-up, and the phone call took exactly 31 seconds. Even apps aren't instantaneous, but if they were, you're only talking about saving less than 1-2 minutes per day. In exchange for those time savings, apps introduce a lot of complexity and overhead: service fees, app updates, device storage, logins, behavioral tracking, etc.
Now, that being said, there are a few unique advantages to apps, like being able to order taxis in a foreign country (as you said), or being able to share your GPS coordinates with the taxi.
