PDF Conversion: Is Adobe really so clueless?

If you download the beta version of InDesign 19.4, you can open some types of PDFs in InDesign. Or you can use a third-party tool: Leguptools, Markzware, Recosoft all offer conversion from PDF to InDesign. However, whichever method you use you'll find the conversion isn't perfect, but should save you time compared to rebuilding from scratch.

THEY ARE BOTH ADOBE PRODUCTS

Should InDesign be able to open and edit a Photoshop file?

I don't know if this will decrease your anger but I thought that you might like to know that there is a third party plug-in available from Markzware that will convert a PDF into an editable InDesign file. Check out https://markzware.com/products/pdfmarkz/ for more information.

Few apps directly "open" any other file formats. Many, however, can convert, import or 'place' quite a few in the regular course of things.

That you cannot open a PDF in InDesign as an editable document should surprise absolutely no one who understands complex doc formats. You can, however, open them more or less directly in Illustrator, and place them as complex graphic elements in ID. A more direct conversion/import process has been on the books for a while but ain't here yet and is likely to remain limited for quite some time.

Sorry you've been inconvenienced.

(And ETA: PDF is a standard loosely implemented by many companies. There is no special reason an Adobe product should be able to open PDFs created by substandard apps and streamlined implementation of features. Like so many things, they are far from "all the same.")