Microsoft was over 5 years (1848 days) later than Apple to "get" what an MP3 player was. During that five years, Microsoft had a total R&D budget of over $25 billion, or $13,698,630/calendar day.
Of course we don't know how much of that budget was allocated for the Zune, but one could easily imagine it being in the hundreds of millions.
You say they got the MP3 player, I say if you throw enough money at a problem, eventually, no matter how hard you try to ignore it, the solution will present itself. And in this case, it was simply to copy their competitors.
edit: typo
