https://www.nytimes.com/interactive/2016/05/19/upshot/forty-...
(I realize that's not the point of the article you linked, and that it's usually the other way around, but the "X% of buildings could not be built today" on its own is just stupid).
I live in a condo that could not be built again under current zoning laws and regulations. And you wouldn't want it to: its not safe anymore (thus new code) and the current sewer is at capacity (until there's a major overhaul there, you can't build anything else).
Sometimes its not as simple as "build whatever!!!". We should be allowed to learn from our mistake and make things better.
If what you have now is worse than you think it should be then the argument isn't valid, agreed. But if you think the way the place is now is pretty good - if the things that are now illegal are the same things that set this place apart from other cities - then the argument makes sense.
Again I don’t think we should evict granny but there are 1 million rent stabilized units in the city. Great deal...unless you’re looking to rent.