Considering majority of the planet doesn’t have access to esim. Google just cut off a huge chunk of its markets. I’ve been waiting on esims for years. They are slowly creeping out but they don’t work on all networks and don’t work on pay as you go plans.
Think you’d need esim to be much more established before you tried anything like this.
BT headphones had become pretty normal by the time they started removing the jack. You can also get an adapter to still use them. No slot for sim would be incredibly bold and lose them a tonne of money.