I'm convinced that in the billions of people living on Earth, there are a couple million that could agree on things that currently divide countries, like this. Sadly they're unlikely to ever be able to gather together in a single state.

The status quo is nation-states in roughly their post-WW2 borders, and it's fiercely protected. The upside is stability and fewer wars, the downside is that the only way to try anything new is to co-opt an existing country. Adding to that, most countries are ethnostates that would prefer to have only a small percentage of their population be migrants. It's an easy way toward social cohesion, you just stay roughly where you're born, with people who were also born there and share the same cultural background. As we can see, it's not ideal - two lifelong neighbours can easily hold completely opposite moral values.