Actually, they wanted the road AND the park. They wanted to share the space, to compromise—two concepts apparently unpopular with absolutists.

Let’s be accurate. It was not a ”freeway.” It was barely a highway. It had traffic lights every two blocks that strictly limited traffic to 25 miles an hour. It was bordered by a wide walking path, and the “highway” was only open to cars on weekdays.
Also, housing is an unrelated issue.

I wonder how much the voters on the North side would be willing to consider closing the Embarcadero or Bay Street?

District elections were put in place by progressives in opposition to downtown business interests. The big-money backers of Engardio do seem to be the 2025 equivalent of downtown business interests.
Sunset voters can’t do “whatever they want” but they can send a message to their supervisor.

There is a larger point. San Francisco instituted district elections for supervisors more than 40 years ago for a reason. Supervisors are elected to support their districts. His constituents told him they were opposed to the closure of the Great Highway. I think it’s called democracy.

And while looking for something else I found some footage of the show I was talking about earlier. Here's the Beach Boys, Jimmy Page, Joan Jett, the Oakridge Boys, and Christopher Cross with "Barbara Ann", with John Stamos and Mr T on drums and Brian Wilson on keytar.