The "most" of the US fire service is just provided everywhere.
But the US is also a very big place with big empty spaces filled with very small communities. Along with strong devolution in governance, there are "some" very remote communities where the population cannot support a permanent local fire service and relies on locally organized volunteers. They can choose to fund that in a variety of ways, by taxes/subs combination. And of course you may live so remotely that even that is not realistic.
But the US is also a very big place with big empty spaces filled with very small communities. Along with strong devolution in governance, there are "some" very remote communities where the population cannot support a permanent local fire service and relies on locally organized volunteers. They can choose to fund that in a variety of ways, by taxes/subs combination. And of course you may live so remotely that even that is not realistic.
I very much doubt the US is unique on this point.