Maybe it was a sign of their maturing attitudes, or the circumstances of their lives, or just a coincidence, that these two consecutive Beatles hits, the first two written after their visit to America, matched love (the ever-present theme in all the early Beatles singles) with real-world concerns like money and work. "Can't Buy Me Love" is a step up, lyrically, from "I Want To Hold Your Hand" but it's still probably not worth drooling over the sophistication of its message. The idea that love is more important than money is pretty standard pop stuff, but it was a very well-written version of the pop stuff. It's a great song, don't get me wrong, and with the benefit of hindsight you can point out it's kind of embryonically hippie, but it's only revolutionary because it's just so good. But they did have to learn how to advance their craft by finding new angles to approach it from, and this was the next step of that.
The thing I've always thought about these Beatles songs from pre-1965 is that they hardly even seem to have been written: like they just happened. You don't think about them in the same way you think about "In My Life" or "Strawberry Fields Forever," and sure they didn't require as much work or personal expression as those, but there was a time before John Lennon sat down and conjured up the title track to their first movie. It wasn't really just always there. Although not everything they wrote was as good as this, this song was sort of the proof that the Beatles - specifically Lennon-McCartney - had a clearer vision now than ever of what a Beatles song was.