I'll be the first one to call it, but the vinyl bubble is about to burst. Too expensive and too available. Gone are the days when the average cost of a Bowie, Smiths, or Floyd album would cost a few bucks in the bin. Now even the most available titles are shilling for no less than $10 at most used shops. Why would anyone charge $15 for a used copy of "Rumours"? I bet if I walked down the street I'd find one in the trash; it's practically everywhere! And the new releases are just as bad. Every artist has their album pressed on vinyl, and every vinyl comes in standard, deluxe, and pre-order editions. The numbers are nearly spot on for sales so the 'collecability' of your newly purchased deluxe album is either cost of lower (2000 pre-orders, means 2000 fans, means market tapped). Good luck trying to flip (if that's your thing) because anyone who wanted that album has it.
I used to love browsing the bins to see what I can dig up, but thanks to the over inflation via eBay & Discogs (and reality tv such as Storage Wars, American Pickers, etc... to some degree), every store thinks they can rack up the price because they think that's what the market is commanding. But it's not, it's just a culture of over value. The vintage gaming bubble recently took a hit for the same reasons, and while vinyl will no doubt stick around it can't possibly maintain the momentum it had in the mid-2000s. It has to plateau somewhere.
...Now bring on October so I can get my 2 copies of the lost PWEI album in glorious 12"!:)