Myself, I've never made enough off that one rap CD to recoup the cost of sending it to CD Baby, so I've got NO skin in this fight. :)
For a music streaming service, looking to recoup your lost royalties after almost 17 YEARS (and only getting 1.5% extra at that) is laughable.
The three months free period is intended to make the amount of paid customer bigger after the three months, so you have to account for that (and you don't). I don't know what is the predicted impact of the three months on the subscription numbers, but let's imagine you would have a two times faster market penetration. After a year you would have 3 months free and then 9 months with double amount royalties, compared to 12 months single royalties.
Number of users who will pay for Apple Music with no trial or a 1 month trial (as per Spotify, Rdio, et al) = x,
Number of users who would not pay for Apple Music with no trial but will after a 3 month free trial = 2x?
Doubtful. I think the order of magnitude in people for whom the three month trial is in the order of single digit percentages, at most (because I'm sure other music services have A/B tested this). "1 month vs 3 month trial" is not revolutionary nor out of left field, and I can guarantee if the there was a 100% increase in customer base by Spotify offering a three month trial, they would be doing that right now.