Can you not imagine that there are consumer benefits to a non-replaceable battery? Benefits that consumers may be choosing?

Imagine yes, believe that this is in fact the case - not so much. If only because they do not in fact have the ability to choose on this.

They had the ability to choose for a long time while Samsung attempted to compete on this feature.

Consumers overwhelmingly opted for phones without replaceable batteries, which is why they stopped being made.

Did they ? Afaik there was never a product line with comparable specs and price points that had a builtin battery and a replaceable variant. Samsung never competed on a battery design - in the galaxy/iphone competition the battery is probably the least relevant differentiator. There is arguably a legitimate user tradeoff here - a builtin battery can provide more capacity for a phone of the same size, but it doesn't mean the users got to make it.

Not just capacity - robustness.

No of course there were no identical products only differing by whether the battery was replaceable.

But that is irrelevant. If it was important to people, phones without replaceable batteries would have been slower to sell and manufacturers would have adapted.

Samsung threw hundreds of designs against the wall looking for an edge, and they all failed except for the ones closest to the iPhone in design or bigger than the iPhone.

Customers did have a preference for larger phones, which Apple was forced by the market to concede, but not for replaceable batteries.