Because the topic is politically contentious. It doesn't matter which new site is floated or who proposes it when there's effectively blind opposition without regard to technical merit.
The reality is that for any objectively defined risk metric we can come up with a solution that involves burying it in the ground at some depth and in a certain sort of surrounding geology. At some depth it ceases to matter despite what the activists seem to think.
Yes, but to be really safe, that point might be so low, it becomes really expensive, also getting it all there without accident - which is the whole point, of course radioactive waste can be treated safe and sound - but that is expensive and people and companies and governments are known to be sloppy.