We could've if there was enough political will though. https://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_r...
[1] https://www.energy.gov/ne/articles/5-fast-facts-about-spent-...
Let me ask you a question then - have you actually seen those railroad casks for nuclear waste? They are incredibly resilient, I'd be far less worried about having those travel through my city than living next to a 70 year old chemical plant(which I do).