It’s a winning argument still. Don’t mistake it with lack of competition in a market. Even ISPs have a limit on fleecing customers before people get really fed up with it and nationalize their business or provide funds for competitors.

We tend to look at these things through a static lens “two major smartphone OSs” and not over longer periods of time, which is a problem in framing discussion. When Ford built their car there was approximately just one car (one OS). If you paused time there you’d apply the argument you’re making to Ford. But over the longer arc of time you’d have been incorrect.