You have to also balance the thousands of square miles of radioactive wasteland that currently exist
Which "thousands of square miles of radioactive wasteland" would that be?
That certainly doesn't describe the area around Chernobyl, which is basically forest like it's always been, with a few people plus a large amount of the usual wildlife.
Fukushima? Nope, no radioactive wasteland there either.
Closest I can come to finding a "radioactive wasteland" on Earth today are coal-ash heaps outside coal plants. Pretty much nothing grows,and the solid radioisotopes make it as close to a "radioactive wasteland" as you'll find on Earth today....