I’ve done it and seen it many times. People throw their phones to each other in pools and the beach for photos all the time. One of the best things about modern phones is the waterproofing. IP68 level is amazing.
> A phone needs to handle some rain droplets falling on its screen, anything more than that is a gimmick that's not worth the downsides it comes with
It’s actually the opposite - a user replacement battery is a gimmick not worth the downsides.
Apple know this, and they know their customers a lot better than you do.
Your position is niche at best, anachronistic really.
> user replacement battery
It's not really the old kind of replace-ability, though. The only requirement is that you should be able to change it with commercially available tools.
Apple has vested interest in getting their customers to switch to a new phone often, and the average time to upgrade is absurdly low these days (less than 4 years), which is greatly influenced by battery wear and fall damage, so I don't think this argument is very persuasive.