I find this video simultaneously awesome and depressing. Awesome because it's funny and Axis of Awesome are very good at what they do. Depressing because it sums up in a few minutes what I think is wrong with modern listeners and why I dislike pop music.
Stock footage. I don't like it, I avoid it as much as I can. Even if I have to use it, I'll at least try to disguise some of it. Most of these songs are blatant about their stock footage, not even bothering with a little bit of disguise. The given chord progression isn't unique to pop music, but pop beats it into the ground. That doesn't make them bad songs, but it shows a lack of creativity. And you may argue that all the melodies are different. Sort of. All the songs in the video are sung by the same guys in roughly the same register, so none of the melodies really break away from a narrow range of notes. And because of the familiarity of the chords, the ear of whoever wrote the melody is likely to be led around in a very similar manner. I bet if you analyzed the melodies you'd find then more similar than different.
I think it also shows a lack of education in the listener. Ok, I'm shooting myself in the foot and insulting all you listeners. But maybe it's a symptom of a larger problem. We live our lives 3 and a half minutes at a time, 140 characters at a time, 6 seconds at a time. There's no time taken for fuller exploration, nor is there any time given for more complex, deeper songs to sink in. Is it similar to the problem that people don't know the Earth goes around the sun, that Titanic wasn't just a movie, and that The Office is a remake of a British show?
If there's a lesson I could point to here, it is to question new songs you hear on the radio. Do you like it because it's genuinely interesting, or because you've subconsciously heard it before. A hundred times. Always rememer this: it's been a long tradition in pop songwriting to write songs that will sound familiar to you. If a song seems familiar the first time you hear it, you're more likely to buy it. Stock footage sells. And if you're a songwriter, don't just rehash the same material because it's easy or will sell records. Stretch a little for the sake of good art.