I have the same problem with iMovie: no older version to install on my Sierra laptop. It sucks that Apple is do determined that everyone MUST run the latest OS.

I really don't care for their office productivity suite because - for me - it encourages too much fiddling with presentation. I just want to crunch numbers and put words on paper, so I use LibreOffice. I would prefer to delete them, but knowing Apple's fondness for not letting you reload them after a new OS generation is released, I'll keep them. They'll provide updates for old versions, just no new install images.