And when you do break things, it’s relatively easy (especially on iPhone where most users upgrade apps quickly) to fix the client, wait for the next release, then remove the unwanted server feature.

Once you have two or more client implementations, you have to keep track of a lot more things, your QA checklist grows, and you therefore need to move more carefully for server upgrades.

In my country, influencers who had iPhones picked it up, and then promptly dropped it because most of their followers couldn't come to the party.

Only targeting the US is folly for a social media app. And even there, iOS has only 60% of the market.

Also, other rich countries, like say some north/west European ones, have a large (~50% or more) share of iPhone users as well.

If you need to go to market quickly, it makes sense to start with the trendy people with money, then you can go for the long tail of Android users.

Edit: Clubhouse isn’t an app where it matters whether every single one of your friends and family is on it for it to be useful/entertaining to you. And if you become established in the most desirable segments of some major economies first, you have a good foundation for going after the rest of the world later. There’s no need to try to cater to every single potential user on Earth from the get-go.