All true, but then who needs Scrum?

And I reject the notion that Scrum is a framework that one can add to, becauase when you add something, you change it. If you add garlic to vanilla pudding, it is not vanilla pudding anymore.

And Scrum insists that you must do it exactly as stated. And the Scrum Alliance does not allow their trainers to teach anything beyond Scrum - in fact, they don't even allow their trainers to be certified in, say, SAFe - in effect saying "you can't know about that so that you could add it to Scrum".

And with so much to add, what good is Scrum? IME it causes people (Scrum Masters) to obsess over Scrum's ceremonies, when other things are more important. As such, Scrum is a huge distraction.

Plus, the core model is a poor fit for a product-focused initiative. The PO should not be shoveling stories to a dev team. One should have a design team involved; one should have beta users involved; one should have information architects involved. There is so much more to consider, and you can't just "add" those things to Scrum - they change how you do things.