Asiasoft's definition of "permanent".

don't think it's hard to make a permanent pink bean chair since on kms the justice shop had one..

The permanent version is different item than the time-limited version. They have to do a couple things to make it happen:

1) patch the quest to give a different reward.
2) replace the ones that have already been handed out

The issues with each of those -

1) They need this coded and a mini-patch issued. This kind of change request may not be able to be scheduled and/or may take longer than the event period to fix. It -seems- very simple, but it's still a hassle.

2) They may not have a way of determining which temporary chairs came from other sources and events and thus if they replaced ALL of the time limited chars, they would be upgrading chairs that were never meant to be upgraded. Again this sounds silly from the outside, but it is still probably a concern.