Apple is not a developer-facing company in the slightest anymore: they make products for consumers by and whole. Every single one of Pascal's arguments is to developers, and his lone point for consumers is really about the operator not letting developers do things all willy-nilly. Apple needs developers, they provide for developers, but their platforms are built for consumers. Meaning that features for developers aren't in the final build.
Repo competition is great for developers, but bad for consumers, in that yes, consumers really do get that confused. "Vibrant, more dynamic, more innovative place" means odd changes and sharp edges, and most computer users don't want that in the slightest. Stable, similar and uniform are awesome for the majority of users, even if the curve is slightly behind what early-adopting technical users want.
You know how some people think that Microsoft Word is their operating system? Yeah.
If it's "all about the apps", then cons for developers mean cons for the users, in the long term.
And then you go and repeat an argument that the blog writer acknowledges as one of the tradeoffs in the article. So it's not like the blog writer disagrees with you fundamentally, it's just that you both have different ideas of the relative importance of "stable, similar and uniform"
And he does list some benefits of alternative app stores for consumers.
Most people will never care about the benefits of competition between stores, and the negative of confusion will greatly outweigh the benefits. I really, really want to stress that. It's hard for anyone here to understand, but computers are pretty damn scary for many people.
Android's app model is much better for anyone who reads HN (me included), but I don't know any non-technical Android users who have ever downloaded an app from the marketplace, let alone side-loaded one.
Your argument would be stronger if he actually said that.
It's not at all clear, though, that these cons for users outweigh the pros for them.
There are all sorts of sites like appshopper.com, though, that provide alternate interfaces to enable such things. It's not like Apple's App Store (and I'm sure Google's Marketplace is no less open in this way) is closed to outside linkage.