Portland is smarter about it. They allow you to build up to a line, and no further. Eventually, they move the line. Assures infrastructure and services can keep up.

It's not necessarily being smarter about it. Urban growth boundaries limit the amount of land available for development, which can drive up the cost of housing significantly. You intentionally create scarcity - even though there's lots of vacant land within the metro area, you limit the land that can be used to provide additional housing units.

There can be public policy reasons why you want to do that (preserving ag land, intentionally trying to promote density, or even planning the timing of infrastructure) - but it's not necessarily a smart choice in and of itself. Very few Sun Belt metros have things like that. And while there's lots to dislike about places like Houston or Dallas, they tend to be much more affordable than places like Portland.

Is that why lots of FL buildings get swallowed by sink-holes? The "benign neglect", so nobody bothers to survey areas that will be prone to that?

Not really. Almost every part of Florida is at least theoretically subject to sinkholes - the entire state is comprised of carbonate rocks - but we've got a pretty extensive survey of the areas that are most at risk (Karst regions where limestone is close to the surface). But there's no way to know in advance whether a particular lot within those areas is going to be hit with a sinkhole going forward, and it's too big to just close that whole part of the state off. It's like more like Tornado Alley than anything else - you know that the structures within that vast area have a higher than normal chance of being demolished in a tornado, but you can't know ahead of time which ones and you're not going to just avoid the entire region.