Unless someone, somewhere, comes up with a stash of them and can re-import them, they aren't going to get any cheaper. Even if that happens, think of it like a stock market crash...you'll take a paper loss, unless you freak out and sell your carbine while prices are low. Wait a few years and prices will be back up where they are now, or above.
Of course, that is only relevant if you intend to sell. If you intend to just keep it, or keep it and shoot it, it doesn't matter, except in the "oh I could kick myself" department. However, unless there is some indication that there is a really good chance that supply is about to open up, I'd just buy one and forget about it. Why? Because worrying about prices dropping for something is a sure-fire way to never buy anything, and you have to attach a value to having and enjoying something now as opposed to waiting and dreaming and hoping to own it in the future. Life is short.
If you want one, buy it.
Mike
PS the real question is whether or not you consider USGI to be worth it, vis a vis a new reproduction. That's something only you can decide. Are you looking for a piece of history, or 'just' a shooter, or both? Me, I went with both. I found a heavily used, but not abused, carbine that had much of its historical value 'lost' via a refinished stock and being a mixture of parts. To me it was perfect- history, without the pricetag. Shoots ok.