Open does beat closed
Apple is the largest vendor of open source operating systems in the world.
Like many people, possibly including Gruber, Wu is under the mistaken impression that Apple is down at the "closed" end of the scale. He fundamentally misunderstands how openness really works in the world of computing. Apple does understand however, because they are secretly a rebranded Unix shop.
It may not seem like a big deal to people who were among the Mac faithful the whole time, but the early "switchers" in the OS X 10.0 and 10.1 days were hugely important to driving early adoption and development on OS X. They were mostly unix and internet developers, for whom openness is vitally important.
The Mac was a superior platform for these developers because of its openness in the respects that mattered to them--compiler toolchains, libraries, POSIX, source compatibility with other Unixes, command line environments, internet protocols, etc. The Internet and web have always been dominated by "open" unix-based systems, and the Mac almost instantly became the Web and Internet development workstation of choice because of how nicely it fit into this world, right at the exact time when the Internet was exploding into everyday use.
The Mac was actually a spectacular success in Internet workstations (especially laptops) for the exact same reasons Linux was a success in the data centre. And when I say, "exact same", I mean exact: the same command line tools, the same programming languages, the same shell scripts, the same database environments, the same web server. It was like your Linux production environment was running right there on your laptop. Just rsync and your changes were live on the real server. Yeah, you could do that from a Linux workstation, too, but setting up a decent Linux laptop in 2003 was an exercise in pain and frustration, and even if you got it working, you still didn't have access to the world of commercial apps for Mac (and, after the Intel switch, Windows). It was the PowerBook that freed the unix power developer to go wild on the Internet.
Gruber is right, the consumer doesn't really care about openness. But developers do, and Internet developers especially. And where the developers are, the consumers are bound to follow, because that's where the cool stuff happens first. Microsoft proved that in the 1990s, and it was openness that drew developers to the PC, too.
Some might argue that the transition from web to mobile means that Apple's closed attitudes with iOS will become a problem. Maybe, but I don't think so. Mobile development is still Internet development by and large, just with a different front-end. The fundamental concerns of the developers are with communications, protocols, service architectures, and "the cloud", and iOS still has those unix roots that keeps it open in the ways that matter to developers. Android has unix underpinnings, too, of course, but Apple captured the cream of the Internet developer market 10 years ago, and Android is a latecomer. They either have to woo away Mac developers who have already made their choice, or they have to woo the ones who stayed behind with Windows or Linux on their workstations, and who enjoy programming in Java to boot. I suspect this factor explains everything you need to know about why Android has the "feel" that it does.