"When is this event coming back! PETITION" threads? Exactly.
There weren't because there was no need to, we used to get the vendor that would sell old gear. Non-seasonal events tho... a lot of people were asking for the Lightning Returns event to come back prior to the Anniversary, and plenty of people still use some of that gear. Lighting's chest, Snow's axe and legs are very popular even now.

And you don't see seasonal gear all year round, but when around that particular holiday people do like to glamour their outfits with event gear, or change their chocobo barding.