Perhaps that's the answer. If waste is stored in a warehouse next to the seat of government, I doubt there will be short-cuts, neglect and cost savings to the same degree as say putting it on the Cumbrian coast.
https://www.parliament.uk/about/living-heritage/building/pal...
So yes there probably would be 'cost savings'
It's too vast to be useful for much, but it does illustrate that the columns and so on in most buildings you do use are not actually obligatory (it doesn't have any). It's a bit like those huge buildings for building space rockets and jet liners, except built hundreds of years before the people who invented those were even born.
Though I thought it was just the palace, ie the Victorian bit put up after the fire (I'm not helping my case here, am I?), that was falling apart.
In the UK theres still some covered market square buildings that still hold markets also.
http://www.endeavourcottage.co.uk/whitby-blog/whitby-marketp...
200 years ago the world was a very different place. I'm struggling to think of any building not including houses still used for their original purpose, from that long ago.
So while I don't doubt that we could build a structure that lasts 200 years, I doubt we could build some kind of continuously used industrial building without it becoming some kind of ship of Theseus. Now that in itself isn't necessarily a problem, except what about a war or something. Unlikely? Yes, but how many countries havent had any war on their soil in the past 200 years?
And I cant imagine a 2219 health and safety person green lighting the reuse of a 200 year old containment vessel for storing nuclear waste either.