How to vertically align a text block at the bottom of a page in Pages?
The only way I can think of is to use footnotes.

They do exhibit the asked for behavior, and you can delete the automatically-inserted number/sign in the footnote itself.

The limitations, though, are threefold:


You have to use end of page footnotes, and since this setting is document-wide, you can't use any other footnote style.
This fake footnote will increment the footnotes count.
Most annoying: the insertion point that is bound to the content can't be deleted. It is good that you can define at which exact point you want your bottom block to be pushed to the next page. However, you will have to make the insertion point invisible, and there is no pretty way of doing it. I guess the “least bad” way to do it is to make the text color 100% transparent, and put the insertion point at the end of a paragraph, so that its spacing does not impact the text around.