Some manufacturers actually do this. NIO particularly does this at scale in China and I believe they are starting to expand to the US and the EU now as well.
But the reason that this is not a thing are that most of your assumptions as to why that would be a good idea are probably wrong.
1) Batteries outlive the vehicle. Not always but on average they do. There are plenty of first generation EVs that are more than ten years old now that still work fine with their original battery. And the batteries in the newer ones are far better than those first generation ones.
2) Replacing the battery is actually not that big of a deal technically if it needs to be done. It's a bit costly but otherwise just a routine maintenance operation that can be done in a day or so. There are of course lots of older EVs with lots of miles that have had a battery replacement at some point to get a second life.
3) most people are a bit irrational about how much battery they want vs. what they actually need. The reality is that most people end up being perfectly happy with a modestly sized battery. Charging infrastructure is rapidly improving and mostly you only need it when you go on longer journeys. My father has had an EV for one and a half year. With the exception of their summer vacation a few months ago, they never use any chargers other than the one at home.
4) Battery safety is just fine. Yes there is the occasional battery fire. But it's far less common that ICE vehicle fires. There are a few hundred thousand ICE vehicle fires in the US every year. And unlike with battery fires, fatalities are very common. Hundreds per year. Unlike batteries, petrol burns fast, hot, and explosively when it burns. Modern batteries are a lot safer than the first generation ones. Manufactures test that by crashing vehicles, shooting at the battery, puncturing them with nails, etc.