[zenogantner]

The problem with collapsed repeated chords comes not only from the data processing -- most Ultimate Guitar songs are written down entirely ignoring how often a chord is repeated -- the classic "lyrics plus chords" format is incomplete and requires the player to somewhat know the structure of the song anyway. The write-up usually just gives hints where, relative to the lyrics, the chord changes.

[moefh]

Exactly. In my experience, it's not just Ultimate Guitar, all of these sites with chord progressions assume you already know how the music sounds. They're not enough for someone to lean a song having never heard it, so they're almost certainly not enough to automate analysis of the chord progressions.