The “widespread pollution” is true in the very short term (as long as you have radioactive iodine floating around), but after that it's pretty much a negligible problem. For instance if you discount iodine-induced thyroid cancer, the cancer rate in the Tchernobyl exclusion zone (for people who refused to flee) isn't higher than in the center of Kyiv (likely because car-induced air pollution is more harmful!).
There are many things that are much more dangerous than the what remains of the fallout from a nuclear accident, that people are perfectly fine living with: air pollution due to ICE-powered cars, pesticide in farm areas, lead fuel near general aviation airfields, or cigarettes, alcohol and even junk food!
People have a very wrong vision of what nuclear fallout actually means, and it's mostly fueled by the nuclear bomb scare in the cold war era. But in the real world even Hiroshima and Nagasaki were quickly re-settled after the bomb with no dramatic effect.
(this is not to say radioactive material is harmless, just that the incorrect perception of its harm lead us to take drastic measures when it comes to nuclear, while we are fine as a society taking little to no measures against much more harmful things)
As for decommissioning, I answered in another comment already, see [1].
[1]: https://news.ycombinator.com/item?id=39287086