Your experience mirrors mine, though I've not built up anywhere near the following you have. First month, my average pay-out for an article was around $25-30, with the occasional monster hit that went to a couple hundred dollars, and the occasional swing-and-a-miss that garnered somewhere between seven and fifty cents.
July hits, and suddenly I'm struggling to see even 10% of those original returns. I'm not here for the money, but like you, I'm thoroughly confused. The stuff I'm posting remains reasonably well-written, but the upvotes vanished into the ether.
I'm not here for the money (I'd have quit already if that was the case), but I'm with you--what on earth happened? :)