I agree in that you don't have to be guaranteed anything. If you want to be guaranteed anything (and really more the guarantee that you CAN do the event), you have to pay the subscription. MMO stuff, yo. Be lucky in that this game you get to have the items come back. In XI, the events had items that never appeared again until about 10 years later.
So yeah...chill, especially considering that you called the items dumb. Why get so worked up over what you say is a dumb item?
Also, the thing about the cash shop (cause that's where all the yukatas are going) is that for events, it doesn't just hold it FOR the event duration. The past event stock is still there since it was implemented last Halloween.
So yeah, if you don't have the cash now, don't worry. You can still buy it when you do.
That's their compromise in concerns to the old event items though. You can't ever miss the old ones now.
They want the cash shop model, it's here to stay. Deal with it.