There's only so much resources on each physical host - when you hit the resource usage of an additional Linode, you've effectively used up the space that could

There's only so much resources on each physical host - when you hit the resource usage of an additional Linode, you've effectively used up the space that could have gone to another customer. So you have to pay their rent as well. Although this really doesn't make that much sense for bandwidth... but when you look at the raw price for bandwidth it's not all that bad anyway.