Even though the use of Flash is in decline and has been for several years, it isn’t going to go away anytime soon, no matter how much Steve Jobs wanted to dispatch it into oblivion. Too many people are making money on it. It helps pay the bills in a way ad blocking plugins don’t.
Google, still writing the book on online advertising, has a dependency on Flash. Like Android, Chrome is a tool for keeping Google dominant in search, which keeps them dominant in online advertising. No changes will ever be made in Chrome that adversely affect Google’s bottom line.