I'm pretty sure most of them develop software for App Store only. Larger market and only one place to get it from, App Store. If you make an app for OS X, it has to be free, otherwise nobody buys it unless it's revolutionary but that would need a lot work. There isn't App Store alike store for OS X apps thus it's harder to get attention.
Steve only cares about iToys and iOSs nowadays. Macs only get silent updates now that MacWorld is non-Steve
You know it's funny but... you can take that entire sentence about OS X, replace it with Windows 7 and things are exactly the same.
Look I know I'm wasting my time here but what the hell: people need to understand that the desktop OS market has now reached maturity. Not just for Apple but Windows as well. There's simply not much else to add in that end users will either need or want. These products are stable, fully-featured and on modern hardware fast enough for virtually every requirement with interfaces that are well established and understood by most users.
It's the same on the hardware side. Yes, the new core i5 and i7 chips are very nice but for the vast majority of people they will never even notice the speed difference in daily use. You can take a three year old Macbook Pro, stick Leopard or Snow Leopard on there and give it to any average user and you wouldn't get one complaint about performance. The need to upgrade we saw in the 90's and 00's is largely redundant now for most users.
And yes, it's the same on the application side. It's very very difficult for any company to make headway in these established markets. The big names are well known and the barrier to entry is high, not to mention people not being willing to pay out for applications for the most part.
What I'm trying to say is that no, OS X isn't being abandoned. It's a $3 BILLION a quarter business for gods sake, why would Apple walk away from that? But you can expect the pace of desktop development to slow down simply because... well... it's pretty much the finished product these days. There's no need to rollout a new version every 18 months unless there's something specific you're doing with that release and right now it's hard to see what that something would be for either Apple or Microsoft.