I'm going to have to disagree with you on almost every point you make here. I am a tennis fan. And a long time tennis player. But I've been to small tournaments (think Newport) and knew almost no one in the field. Does that mean I can't enjoy the match I'm watching? If I attend a Milwaukee Brewers baseball game, as a baseball fan, is there a certain percentage of the players in need to be able to rattle off to someone at the gate to be let into the game? God forbid I enjoy a beer -- that would make it an event!
Athletes are entertainers. Entertain me. That's their job. Part of me thinks tennis fans should be able to talk all they want. And even walk back to their seats mid point without the chair umpire losing his mind and stopping the world because a player can't serve with someone walking down an aisle? A baseball player can hit a baseball with screaming fans, a LOT of screaming fans. And hitting a baseball is of course much more difficult.
If tennis can allow robot linesman anything is possible, right?
You are free to disagree all you want of course. But the point I was making is not that people have to know the players - that was just an illustration of the crowd not being tennis savvy, and therefore not knowing the etiquette.
When it comes to the crowd walking around, they have loosened up on that a lot in the last few years, and I agree with that change to a point. If there is someone directly behind the players in the seats close to the court they will hold play, but in the upper areas of the courts they allow people to move around freely. I think that is a good compromise.
I've been to the Australian Open 3 times in the last 15 years, and the crowds have definitely become more rowdy, and that is partly due to the increasing popularity of the event. The first time I went was in 2010, and the attendance that year was about 650,000. When I went in 2019, it had jumped to around 800,000, and this year the set a new record of 1.2 million people (more than the 2024 US Open, and the largest of the 4 majors until we see what this year bring when this event is over). So in 15 years the event has basically doubled in size. Just trying to find a spot of ground near the main stadiums to sit down to eat was difficult. There are more non-tennis fans there, but other than matches where Australians were involved (or one with some South American countries - one match in particular comes to mind), they were pretty civil. One evening when we watched two Aussies play (a ladies match first then Draper was playing Kokkinakis) was a nightmare, with one guy yelling between every point, but even he knew to shut up during the points. It was a 2 set match followed by a long 5 setter and hearing this guy for 6 hours was brutal for everyone (we didn't get out of there until nearly 1 am).
The noise is something that is a bigger concern for a few reasons. One is that the umpire needs to be able to stop play, so the players need to be able to hear that if it's needed. That's what set the whole Medvedev thing off, when a photographer walked onto the court. But I also saw near the end of one match all the kids come down with their tennis balls ready for autographs, and one kid let a ball fall from their hands and it rolled onto the court - that's a safety issue for the players. I've also seen the extra ball that many players have in their pockets fall out during a point - again a safety issue that calls for play to be stopped immediately.
Another is that the players need to be able to hear the line calls. They don't want to be trying to run down a ball that is out and risk some injury or expend extra energy because they didn't hear the line call. Without real line judges that gave a verbal and visual signal, we only have the audible calls now, so the players need to be able to hear those.
But the more immediate thing in point after point is that the players need to be able to hear the ball being struck by the opposing player. If you don't follow tennis a lot you or play it you probably are not aware that the sound of the ball coming off is one of the first clues the players get to what kind of shot is being played. You need to hear if it's a mishit. a shot with a lot of top spin, or a shot with less spin. It can also tell you how hard the ball has been hit - the modern game is so fast that not being able to hear that is a real problem for the pro players.
Your baseball analogy falls flat in this case because hitters don't rely on the sound of the ball coming out of the pitcher's hand, but they do rely in part on that sound of the ball being struck by the other players racquet. This is why they not only need to tell people what the etiquette is, but explain why it is what it is...