Many years ago, I saw the Canon A-1 camera and really wanted one. Even though I personally knew the local Canon dealer, he said that every last one he could get was sold in advance and if I wanted one 1) I'd have to join the queue and 2) I'd have to pay full price. So I did, and was delighted with it. Six months later, the price had dropped over 30% and was still going down.
It's still the same today. But now, if I want a new camera, I DO NOT rush out and buy it as soon as it's released, even if I'd like it. I wait for a few months, or wait until there's a special sales day at the camera store. I once waited outside the store in the cold for hours, to be first in the queue to get £200 off one of the first five sold that day.
So while it's easy, and understandable, to get annoyed when prices drop, remember that 1) it's not just keyboards, it's just about everything new in the tech field and 2) if you want to be among the first owners, you must be prepared to pay the premium.