Reading Gruber’s post about iPhone app quality over quantity. His argument is that the iPhone has so many apps because of its quality.
The danger I see is in conflating cause and effect. Is the App Store popular because the iPhone is great? Or is the iPhone great because the App Store is popular? There’s a big difference between those two arguments. The latter is the argument Microsoft has long made regarding the advantage of Windows: Windows is great because Windows has the most software and most developers.
It’s not one or the other, they are two different aspects of a computing platform. Looking at it like mac versus windows is helpful. The mac has super high quality apps for things people do a lot. Transmit is the best ftp app, Textmate is the best text editor (in my opinion of course!), Tweetie is the best twitter client. These are quality apps. The mac is great because it has the best software.
Windows on the other hand has more apps. But this is a honest feature separate and apart from quality. If you want to use a gui text editor you would be better off with TextMate on a mac, than Notepad++. If you want to karyotype some metaphases though you can either get Cytovision for Windows, or just not do it on a mac. There are a lot of niche apps that simply don’t exist on macs. Windows is great because it has the most software. If you’re using niche apps, you get stuck on whatever platform has the most software frequently. Sure, I’d love to use a well designed app for karyotyping, or for pathology informatics on a mac, but they don’t exist.
Right now the iPhone is great because it has the best software and the most software, but it’s not an either or situation.