I think about it like this. Lightroom has a huge market-share lead on Aperture. According to Infotrends, in 2009, Lightroom had 44.4% market share on the Mac platform versus 12.5% for Aperture.
And I believe those numbers – I just don’t run into many other Aperture users out there.
So that’s the primary motivation – simply to catch up with Lightroom.
Now the biggest problem with Lightroom isn’t that it’s a non-Apple product. No, the issue with Lightroom is that it’s a cross-platform product.
See, if a person starts using Aperture, there’s a good chance that they’re going to stay on the Mac platform because Aperture is a Mac-only piece of software.
On the other hand, Lightroom users have the freedom to switch between Macs and PCs. That gives Apple an even stronger incentive to push Aperture as hard as possible.
And finally, I think Apple wanted the Mac App Store to make a big splash, and offering a blockbuster deal on an amazing product like Aperture 3 was a great way to generate press about the great deals in the store.