Obviously, there's many other factors at play. SEO is a complicated world, especially in such a crowded place as song lyrics. Though I noticed Google actually has an inline box for lyrics now which avoids the issue entirely.
Yes, there are many factors, and I clearly don't know all of them. I definitely see the problem that Google's inline (or amp) is trying to solve, but I think encouraging the right sites to grow to the top is a much better solution.
And by construction, AMP pages are easy to analyze without having to execute anything.
(disclaimer: I work at Google, and used to work on Search)
In no way was I dissing Google's crawl or crawl team. I'm just handing out conservative advice for website owners.
(disclaimer: blekko Founder/CTO. Nice to meet you.)