They're also awful to maintain over time, if you're needing to add new elements and require new columns or cells (and then there's the need to nest tables when using them for layout).

I attempted to fix a website by adding closing table cells that were missing, and finally got the page to validate as XHTML Strict and Transitional. The entire layout shifted, and was completely based on those missing end tags.

it's really not. It requires adding a single attribute to tables that exist for layout.