Say Verizon creates its app store, promotes it, and removes Google's Marketplace. They also make sure you can't install apps any other way, including the original Google's marketplace.
Now, they have been able to do all of this because it's open, so yeah, it is more open. However what they will hand over to the customer is more closed, and possibly a worse experience.
Of course, I am paying $20/month for tethering on top of my unlimited data plan. The phone by itself is unlimited, but when other devices connect through it I'm limited to 2GB/month before ungodly data rates kick in. For now I'm saving it for emergencies, but so far the web browser and email connectivity are good enough that I don't think I'll even need tethering, so I'll probably cancel it.
I guess I was looking longer term, but I wouldn't be surprised if "don't close the system" is the new "stop messing with what I like". ;)
The point I wanted to make in the original comment was just to debunk one of the arguments he was making for why Android is closed.
What the US seems to be missing is some sort of protection from the government (regulation).
All in all: open is much better then closed, especially when branding of mobile operating systems is so common. It's not only Android, but also pretty much every other mobile phone that contains such apps.
As others have mentioned, this has nothing to do with the openness of Android but only with the carriers intentions, which have been doing this years before android on closed systems.
Even Adam Smith, the very father of capitalism, did not trust businessmen, and pointed out that it would not work in case there weren't plenty of supply and plenty of demand.
The mobile market is not a free market. It's an oligopoly. Admittedly this is due to a limited spectrum resource so there's not much that can be done. But in an oligopoly is veeery easy for companies to stop competing and try to keep the status quo.
Case in point: the RIAA and movie industry, and the fact that neither are CD at the equilibrium price, nor is either really innovating. Another case is academic journals publishers (there's another oligopoly there, and prices have been going up), oil cartel etc...
So "this will be regulated by the market" is not an argument: if it were it would have been regulated even before the iPhone and Android arrived, but it wasn't was it?
(sorry for the tone, and I understand in the USA people have grown up with this pseudo-religion, but maybe you are different. But you have no idea how many times "free market" is used as a panacea.)
(Forgive me for the quick soundbite. I'm googling for the articles I remember about how horrendously difficult it is to buy spectrum use rights in the US. It's not like buying lemonade. Like many regulations, wireless regulation was designed to protect the established players.)