Effectively yes. Basically, they own the TLD and can sell any domains under that. So, if you want thechthrowaway.blog, you've got to pay them to purchase it. In reality, you will probably purchase this from godaddy or similar, but ultimately they own the namespace and set the price on the cost of the domains.

They purchased the right to issue domains under that TLD as the registrar, I believe. That means they can set and collect the price for domains registered.

It means that Automattic gets a share of every .blog domain sold or renewed, and gets to enact policies around what .blog domains are available (like, can you register emoji in domain names) and other arbitrary restrictions about what can be hosted on the TLD (for example, Google was also bidding on .blog to restrict it to only Blogger sites -- but Automattic bid against them so you can do whatever you want t with your .blog)

Basically, it's an investment both in an open web and in a return on investment over the long term depending on volume of registrations.

The registry ..