Earlier quoted context omitted.
As I understand it, two problems are: 1) There's no clear definition of what it's "supposed" to. Not everyone who uses the term PWA wants the same things. 2. Some things are just a lot harder to implement than others.
1. if 90% of the people don't want a toolbar in a PWA (I'm being generous about 10% wanting it), it makes sense to not have it 2. It is not harder to implement a button to show the toolbar menu In all case, it should be (it already is by the spec!) a developer option, not something enforced by the browser.
(Also, I don't think there's a single "PWA spec".)