There’s precious few places on earth that don’t have room for landfills, and those places will be shipping their refuse whether it is sent as “recycling” or as trash. The article also points out that incineration is an option to reduce volume, but expensive.

There are cases of shipping trash around, but it has more to do with it being cheaper to send a container of garbage somewhere than dispose of it locally.

Cost is the constraint, not available space.