I get that if you saw this when it was released or growing up you'd have some nostalgia for it and it's cool to see as this type of film isn't really made anymore, but it really hasn't aged well at all. Plot is very thin, most of the music isn't really remarkable, and it's way too long at 2 hours.
shareI used to have a very similar attitude to this movie that you do...it just seemed like such a boring, dull, unrealistic movie to me (FYI, this movie was made well before I was born...I'm 53).
However, a few years ago, I finally sat down to watch this movie...and, this time, I loved it. I just "got it" this time...the movie didn't change, I did. It's turned into one of those movies I have to see at least once during The Holidays.
I don't think you're necessarily wrong in your criticism...except for "the music not being that remarkable." The song "White Christmas" by Bing Crosby was a juggernaut...I believe it held the record at time for most records sold. Something about Bing Crosby's voice just fits this time of year, IMO. I think the music (and dancing) in this film is great, "dated" or not.
I think what appeals to me is something you alluded to in your post...the world that this movie was created in no longer exists, the actors/actresses are all long gone, etc. It's almost like a "time capsule" of the early 1950s in many ways. I find it very interesting...and there's a part of me that wishes I had been around then as well.