I’m sure there’s a perfectly good reason why we haven’t done this yet. Too expensive? Would launching it into the sun cause the smoke (if there is even smoke in space) to find its way back to Earth, therefore polluting the air?
This is an incredibly stupid question.
Also by river from wealthy countries, and has done so for centuries.
The scope of the task of removing it is far bigger than OP can imagine.
https://ourworldindata.org/ocean-plastics
Rich countries tend to have better functioning waste collection and disposal services.
These days it is a lot better, but it wasn’t always that way.
It has been that way for many decades.