You already have adaptors so what's the issue? Seems those that need them have bought them. I'm sure current sales aren't enough to justify continued production of the things. It's not as if people are buying new original MagSafe adaptors at this point and need to update.
I haven't bought one yet, because I don't need one yet. That will change in about a year when I replace the MBP I bought three years ago. Like several other people in this thread, I have multiple adaptors in multiple places, and I'd rather pay $10 per location than $79.