I do not believe baseball is declining in popularity. MLB revenues would seem to suggest otherwise, as would the explosion of travel baseball over the past 15 years -- a phenomenon that, especially at the younger ages, I view as proof positive that the Williamsport approach of 15-20 games per year, all in the spring, just isn't meeting the demand.
I do think there was a time when baseball was the # 1 thing for Americans outside of working. The National Pastime as it were. It has been supplanted in that regard by video entertainment in all of its forms -- something that didn't exist 80 years ago that has pretty much taken over the national consciousness. And given that other sports copied baseball's model of taking a game people played for fun and turning it into a spectator sport with paid players, it's only natural that it not remain the dominant viewing option. Though it probably still consumes more TV broadcasting hours than every other sport combined.
On other points: The worst pop song ever was "Run Joey Run" by David Geddes. Geddes wrote some classics that are still sung today, but that one was some sort of a joke that somehow charted and achieved earworm status in my youth. Best pop song ever is hard to pick, but "Uptown Funk" is a recent entry in that sweepstakes.
Ted Williams story: I was once on a cruise ship maybe 25 years ago, and it turned out that a Cincinnati-area travel agency had sold a lot of rooms on a "cruise with the Reds" theme. I got to meet Marty Brennaman, Brett Boone, Jim Bowden and Jeff Brantley. But of course, Sparky Anderson stole the show. His best yarn (bear in mind this was in the early 1990's) was: "Somebody asked me if they thought the old players could really compete against today's pitching -- for instance, would Ted Williams hit .400 today? And I said, 'No, I don't think he could.' They were flabbergasted. But I said, 'Hey, you've got to remember, Ted's what? 75 years old now?'"