If the songs were in lumps, then you would expect to understand what was going on in the plot. Which is not a realistic goal. And also the instrumentation is different for every show, so it's more varied sonically. And people are free to make up their own plots, of course. There are pretty dense and complicated plots, and they're simple songs.
Stephin MerrittI don't remember things initially when listening to music. Like, I don't remember where I first heard a song, I don't have nostalgic attachment to a song in that it reminds me of such and such a time or place. I think I probably did experience that somewhat when I was not a full-time, professional musician, but I don't think music works that way for people who are in it constantly.
Stephin MerrittWhen you're making a singular pop song, you don't really need any subject matter. You just sort of say, "Uh, I love you." And then you try to figure out some rhyme for that, and there never is one.
Stephin MerrittWell, there are certainly original things to say. But I'm not sure that a pop song is the appropriate format to say them in.
Stephin Merritt