Like most things, Razing in realty was a lot more complicated than it ever has been in the game.
First, because a city that has been in one spot for any length of time is there because it is a Good Spot For A City: where trade routes come together, where a river/lake/sea/ coast/combination provides both routes and resources to 'feed' the city, where the city provides a political center for a region/state/empire.
So, IRL where cities have been 'razed' it is almost always because a bunch of the supporting factors were also destroyed or modified or shifted:
Rome went from an estimated 1,000,000 people udner the Empire to 30,000 by end of the 6th century. Not only because it got sacked multiple times, but also because the political center moved away and all the long-distance trade routes that supported the city disappeared along with the political cointrols.
Chingis and his Mongolian armies destroyed virtually every city in central Asia in their conquest and destruction of the Khwarazmian Empire 1219-1221 CE. Every one of them was rebuilt/back to 'normal' within a few years - because the trade routes were still viable, in fact protected and expanded by the unified Mongolian Empire stretching (by the 1250s CE) from China to Baghdad. All of those cities (Samarkand in various names probably the best known) were founded as Trade Hubs and flourished as such, and were too important as such to be allowed to disappear - until, of course, the Trade shifted, largely due to sea routes being opened up starting in the 15th century by Europeans that by-passed the overland central Asian routes in use since the bronze Age.
So, 'Razing' in the game is just a short hand version of what would be a much more complex process to model exactly. Take away all the imported resources from one of your cities in the game, though, and watch it stagnate rapidly: a less-vicious way of showing the importance of long-distance trade in 'building' and maintaining cities.
