I was just checking out thedomains blog of Michael who is also into the new gTLDs and saw his latest article about Rick. Looks like the new gTLDs are getting more and more traction with serious domainers entering the arena
Subdomains are actually being marketed and sold like generic extensions: Centralnic is specialized in this business and sells 'registrations' in subdomains like:
.de.com .uk.com .gb.com, even .co.com etc
Of course, it's an awful deal because of the confusion.
Subdomains were popular in the 90s when domains were more expensive and less mainstream.
Subdomains probably wouldn't fall under ICANN rules; therefore, Rick could just about create any TOS (mostly for his benefit, of course).
Also, from a tech POV, how does one manage subdomains and change nameservers. Does Rick offer a customer panel for managing subdomains, or does Rick or his staff have to do it for the customer?
These are real issues to consider before "renting" a subdomain from anyone.