I agree with you that the requirements for permanent safe storage are very high - thousands of years with no leak, besides others - but nonetheless, even with simpler requirements, Yucca - or any other georep - was not deemed safe.
It wasn't so much deemed unsafe as not safe enough. Pretty much everyone involved threw up their hands and said screw it we'll store on-site which is WAY less safe than Yucca or deep bore sites. Meanwhile we have casks exploding in New Mexico which should have been buried 3 miles underground decades ago.
Mostly NIMBY problems that apply for the repository apply for transportation, but in lesser scale. Yucca was not as dry or geological stable as initially thought, and the requirements for "permanent" disposal are very stringent, so Yucca is not considered anymore for long-term storage.
I think the closer comparison would not be Yucca Mountain so much as deep bore hole research. You could essentially use the same equipment for boring your reactor hole to create disposal pits.
Maybe a breeder reactor would still be built to burn all this "waste" which is 90% fuel. Nuclear fission energy can become way cleaner when the political logjam around extracting and burning plutonium is unclogged.
It depends on what you define as long-term. For a few decades, with proper inspections, sure. For the geological time frames needed for nuclear waste disposal, definitely not.
