Pretty much nailed it. In theory, we can build fail-safe reactors, but it wasn't done. It's nearly impossible to overestimate a life-cycle cost for a reactor, given that there'll be many decades of stuff to deal with even after it's shut down. In the US, the Nuclear Regulatory Commission hasn't fulfilled its original mission faithfully. Why would we expect it to do otherwise now? Properly licensed, designed, built, regulated, and inspected reactors are very expensive. Economically, particularly taking into account the uncaptured costs of using nukes and fossil fuels, reducing usage and utilizing renewables just makes sense. Save the nukes for spacecraft, other planets and moons, and submarines, if we must have them.
Here's a thought... Who profits from building reactors? Who profits from operating them? Often not the same entities. If the operators fail to operate them safely, the builders suffer from loss of future jobs. Maybe if the builders retained some say-so over operation, there'd be more safety. Of course, that fails to account for the effect of prioritizing quarterly profits ahead of long-term viability.