Funny, I know to hit the spam button at the top and the unsubscribe bottom buried in a link at the email footer. Am I blind? Have I somehow clicked "spam" and "unsubscribe" hundreds of times without seeing an obvious "unsubscribe" button at the top? Very dubious.

Nope! Just checked Gmail WebView. There is a toolbar at the top with a very prominent"spam" button, and two kebab menus with "filter messages like this", "report spam", "report phishing", but no unsubscribe button.