You're downplaying the fact that, buy your summation, regardless of when a customer buys something and then that same item goes "on sale" at a later date, it is some how the retailers responsibility to make it right or otherwise that retailer isn't providing good customer service. That train of thought is beyond flawed.
Like I said, a day or two after the purchase and then the item goes on sale...ok, MAYBE you have a leg to stand on but I still wouldn't chastise the retailer if they chose to say "sorry, that wasn't the sale price then" but to complain about making a purchase and then a week later it goes on sale? I think that goes beyond rational thought and favors more a child stomping its feet and pouting until it gets its way. It's thinking like this that has bastardized the act of "customer service." Once upon a time, our society would've just been like, " I missed out on this one. Hopefully I'll be able to take advantage the next time around." Today's society is one that has been coddled into believing if they bitch long enough and loud enough they'll get what they want.
That said, PSA took care of it, because that's what they do. I simply stated they were more giving than they had to be or I would've been.