I don't know what's "average" these days as crazy as the weather is, but I do know this: Buying a tropical line for PA stream/river fishing is nothing I would consider, that's just a waste in my opinion, given that our weather is hardly tropical for the majority of the year. You may have bought the wrong line in that the coatings on that particular line of fly line may not be as tolerant as some of the others in extreme conditions, but for the bulk of the year, I'm sure it will fish just fine here in PA. Then again, who knows, other freshwater lines may not have held up well either. This heat wave has been brutal.
You may have hit the peak/extreme conditions with that line, or perhaps not. I'm still in the camp that a good cleaning & good dressing are in order. 3 times may or may not make a difference in how dirty the line is. I haven't fished the Suskie but as you noted, the water quality is not exactly clean.
I don't consider the response BS. Without knowing all the details, it seems the response provided came from the line manufacturer, of course they are going to recommend another fly line more appropriate for those conditions. Whether you choose to act upon that is entirely up to you.
Sometimes in my line of business, I am asked to provide recommendations to customers that are faced with a challenge. Sometimes they like what I have to say, other times I'm sure they don't. I stand behind what I recommend taking into account their given situation and the options available to them. Of course they are able to look at 3rd party options, act on my recommendations or do nothing at all and make what they have work.
