Planned obsolesce are anti consumer and increases sales. So yes anti consumer design can increase sales volume, that is often the point.

Replaceable batteries lets you use your phone longer, that means people will take longer to buy a new phone and reduce iphone sales. Such anti consumer moves requires regulations to be fixed, since there is no incentive for the company to be pro consumer here.

That relies on the questionable assumption that consumers don't understand the overall value proposition.

The point is that the incentives are not pointing towards "make better phone" they are pointing towards "sell more phones"

Sometimes "better phone" drives "sell more phones"

Sometimes it doesn't.

Very often it does, certainly more often than a government regulation results in a better product.

Can you explain your reasoning? Is there some minimum sales threshold required, and 2 million iPhones wouldn't meet it?

If people buy more of a product, that's because it's better in some way. Maybe it's cheaper, or maybe it's better quality.