In my opinion, not only the need for allowing as many domain names as possible to be registered was the reason for decreasing the registration price, but also the logic behind the free speech concept hidden also in the bitcoin protocol. In the crypto-currency realm, everyone can pay anyone, thus supporting any project, endeavor or enterprise, without any smallest censorship ever. Translating that into the namecoin system means that owning a domain name cannot be stopped from now on by anybody (because no ICANN is present here to restrict as its will any freedom of users). Let's not forget that a name is a basic right, like the information is a public asset, too. A name is meant to be owned, displayed and associated with a brand or content. If anyone would try to own 5000+ names, without any content, that would "empty" the value of these domain names, will freeze the market for them and will decrease the value perceived or even claimed by that greedy owner.
Imagine (as an analogy) that someone would own 5000 servers worldwide, trying to extort people in need of a webhost with a large bandwidth and 100% online time. People would simply avoid these servers (if overpriced) and go elsewhere, even host their websites on their Android devices as a last solution :). Creating something as namecoin offered people the freedom, in the meaning that if someone would take over the majority of .bit domains, someone else could create in no time a clone of namecoin, for registering an create .bix domains, then .byte domains and so on (even dot www, if needed!) ... So the cheap option of owning a name is similar to the affordable option of having a license plate on your car. Do you have that car ? The govt will invent new numbers in order to be able to let you register the car with another license plate different than the one of your neighbour. It is very simple. The point is not in just simply owning the names, but the websites that created first time the inside value for a brand.
As a conclusion, the price is irrelevant, as time as it was just opened a path to almost unlimited supply of domain names !