Replacing battery in iPhone is very easy. It's stupid to replace the entire phone because of battery. iPhone is a good citizen in that regard. You can either do it yourself or ask any repair shop.
It used to be easy to do yourself but it's becoming increasingly difficult and risky given all of the advanced parts that can be damaged or improperly put back when closing it.
And starting with the 12, Apple now requires authorized repair shops to use heat to open the phone, something that was previously only done for iPads and was prone to causing repair problems for the casual tinkerer.
The same is true of watches and nobody is calling for an act of congress about it. If you want something to be waterproof and small and lightweight, you are probably going to trade off some service accessibility.
They haven't gone out of their way to make replacing batteries difficult, but it is more difficult than it used to be before phones were waterproof and tightly packaged.
Sure, it requires special tools, but isn't a battery change on a quartz watch pretty easy? I think the going price for a battery change is like 10€. There can't be that much hard work involved with pricing like that.
I would respond that replacing a battery on a modern iPhone is similarly easy. The tools are plastic, cheap, and as others have noted, are often bundled with the battery. The only price delta here is the cost of the battery itself.
The same is true of watches and nobody is calling for an act of congress about it. If you want something to be waterproof and small and lightweight, you are probably going to trade off some service accessibility.
My watch (Timex) does not require special tools in order to replace the battery, and it's waterproof, small, and lightweight.
I unscrew four small screws on the back using the same screwdriver I've used for years to tighten the screws on my eyeglasses. Pop in the replacement coin cell battery, and screw it back together.
It can be said about iPhones. I like having a thin, light and watertight phone. If the cost of that is limited avenues for servicing, that’s a tradeoff I am fine with.
If the impact on society is significant enough, society can and does forego individual judgment. You wouldn't be able to put asbestos in your house today even if you were fine with the associated tradeoff, because society has decided that it's just out of limits.
You do not need to make it end-user serviceable to make it environmentally friendly. You can make it serviceable with the tools and skills available at a mobile phone repair shop, which almost everyone has access to.
