This is true, but in like 95% of cases, the ZIP code determines the state and the city (and the county, when it matters). Pre-populating them would save time to

This is true, but in like 95% of cases, the ZIP code determines the state and the city (and the county, when it matters). Pre-populating them would save time to a lot of people. Those few with the luck to live at zip codes that span cities and cross state borders would still still have to fill these in manually, like the 100% of us currently. It's a pure improvement with no downsides, except the downside of slightly changing the 100-years-old sequence of address fields. Put the ZIP code first, and your customers are going to be happy with that.