Because nothing was wrong with the batteries as far as we could tell, and Apple "support" didn't mention anything. That's the whole point of these law suits. Apple didn't tell consumers that a) their batteries were degraded or b) that performance would be dialled back to compensate. If people were told they would have just swapped batteries, as we would have. I'd much rather pay $150 for a new battery than $1000 for a new phone.

Prior to iOS 11 they still lasted all day, no random shutdowns, no issues at all. After iOS 11 the phone was slow as hell and the battery drained extremely quickly... the opposite of what you would expect given the recent revelations, but that's what we observed.