If there were going to be a couple dozen canonical/core plugins for everything you would ever need, then there might be cause for concern.
But the idea behind it is for something like (pulling this out of my hat) a twitter plugin. there are *thirty* twitter plugins in the repo. A new user has no idea where to start there. A core twitter plugin would have these advantages:
- a team of people working on it, instead of some guy in his spare time
- a core dev looked the code over for vulnerabilities
- guaranteed to work on upgrades because someone official has an eye on it
Now, we could argue that more choice is better, but - REALLY? 30 plugins, where half of them do the *exact same thing* is not a real choice. Added bonus is the developers will be able to work more closely with other developers - not in isolation. They are planning on making it easier to do that for devs or those who wish to dev. You know, sharing knowledge & learning from one another?
BuddyPress, for example, is a *perfect* one to look to. No, it's not going to be bundled, but it is worked on (a lot), not going anywhere (but up), and core devs have given it a look-over. oh, and it's free. A win for users.
on the commercial side, this still leaves room for it. Even with BP, there are paid plugins for features that haven't been added to it yet. one dev can often get something out real quick & sell it to those who want it now and can't afford to wait, so they'll pay for it.
Let's take another example: say a contact form was a core plugin or even bundled in. Would this put gravity forms out of business? Probably not for a long, long time - if ever. There's plenty of notice for devs, enough so that if Carl did ever have to adjust things, he'd have plenty of warning & time. And there are always people who are willing to pay devs direct for better assurances of paid support (not guaranteed with core plugins either).
I do take a bit of umbrage with the post's tone of "It's the American way in a capitalist society, darn it!"

We're not all American. The Internet is global, and so are many WordPress users. We're not all interested in capitalizing it as much as possible. And there are some plugins that died an early premature death (podpress anyone?) that could have been prevented had they been a small team with an official "approved" stamp.
edit:
Actually, I think they're trying to make it *easier* for those working in isolation to become closer to the project, and work on their own projects with more help. There's no preventing anyone from still going off on their own.
Jeez, considering the amount of complaints I've seen about the plugin repo being full of too many outdated & duplicate plugins, you'd think those same critics would like this idea. Which was put forth to partly help exactly that.