In the 1930s the answer was to create a job guarantee in the form of a massive public works program. That's how stuff like the Brooklyn Bridge and the LA Griffith Observatory got built.

The other option is to keep the retirement age down. I'd like to know why so many people who believe in this automation revolution are instead advocating for the exact opposite on the grounds that we actually really have the opposite problem...

You can't take both sides of this fence. Either the automation revolution is real and retirement ages can be lowered or it isn't and articles like this are spouting horseshit.