Zoning codes have some uses, doesn't mean they're still net positive value. Maybe the current situation is so bad that letting a pig farm or a coal power plant be build right in the middle of a residential neighborhood is actually a better tradeoff than whatever we have now.

In many European places there are only a few zones: farming/industry, mixed commercial/residential, and of course random other stuff like parks. And when you build you can only go a couple stories taller than the average in a certain radius unless you're explicitly approved to build a skyscraper. This height limit is also displayed on the zoning map but I believe it's regularly adjusted.