It's interesting how many younger people in the US aren't even aware that the only useful decongestants are behind the counter. I assume they just think there isn't a useful treatment for the symptoms.
I remember when the over the counter stuff just seemed to stop working. I just assumed that something about my body changed. Took me a year or so to find that the ones behind the counter still worked very well.
I think I'm lucky, in that I don't really need too much help that often. I can only imagine if my sinuses were as bad as they were back in the day, though.