Actually, it's good news. Here's why
My reading is that Apple is largely concerned that software that does "X" (insert values for "X" here) is available on the Mac platform. If it's cross platform, then the more the merrier, as that aids Apple's interoperability, which while they remain a minority platform, is very important.
If Adobe is coming out with a competitor, still more a, so far, well received competitor, then it most certainly is in Apple's best interests to "drop" Aperture. Dropping it aids Adobe and aids the third party product that has a chance of being cross platform.
By aiding Adobe, it also strengthens the confidence of third party developers who support Apple. They know that unless they screw up, Apple isn't always going to sweep in and steal their lunch money. This is probably the most serious problem with Windows at the moment, Microsoft has, time and time again, driven third parties into the dust.
There's no point in Apple competing with Adobe if it doesn't result in a significantly better product aimed at the same market. It's a waste of Apple's resources. It drives home the message that Apple doesn't care about third party support. It doesn't add anything to the Macintosh platform. It undermines cross platform compatibility.
Aperture has done the job it was intended to do. It has proven the credibility of CoreGraphics, and it's proven the value of a particular type of tool enough that other people want to create those tools. Let's not get disappointed by a decision from Apple that clearly doesn't harm the platform at all, and will give more confidence to developers to develop great things for the platform. There's more cause, in my view, to mourn the passing of AppleWorks than Aperture.