India's top 5% can afford a $1000 phone somewhat easily. India's top 5% is about 65 million people. That's a lot of potential volume. Will the iPhone be main stream in India? No, of course not. But India could still be a bigger market than California, especially if India's GDP continues to rise at ~6% per year.
That same top 5% who want the $1000 iPhone, already have the $1000 iPhone. They don't care about the additional cost due to tariffs, hence not a point in this conversation.
You are right to some extent. Some portion of that market that wants an iPhone is already getting one, sure. But some portion of that market isn't as well.
I can afford a $10k iPhone, but there's no way I'd buy one at that price. Price matters to almost everyone beside the top 0.1%.