I remember pulling up crash logs for people showing them that Flash was in every one of the Safari crashes the wanted me to fix. I told them it was out of my hands.
The main reason other browsers stopped supporting Flash was websites stopped being built with Flash because iOS didn't support it, and a lot of people thought that mattered even though iOS had (and still has) a small market share world-wide.
Sure, he's laying out a case for the app store they'd later introduce, but it wasn't simply CPU and battery. There's a reason I cited crash logs as the primary thing I remembered about how it affected me. It gave me an immediate reason to share with people about why I couldn't fix Safari crashes when Flash was involved, which made that aspect of my job easier to explain.