I suppose if it becomes expensive then the namecoin admins could lower the cost of database inserts/updates. But it seems like that would prompt the price per namecoin to rise accordingly, because the value of namecoin is a single database insert or update.
That said, I actually think the BitShares Domains model is a better fit for name registration: treat each domain like real estate, putting it up to the highest bidder (which makes squatting expensive). However, BTS Domains is probably a year away at least.
In either case, the most significant bit is browser/OS adoption. At the moment, not a single browser (even Firefox) supports .bit domains, except through plugins.
Is this like rent? It may make squatting expensive but it would also make non-commercial websites impractical.
I hope it fails.
However, at the moment it's purely in the planning stages.