Slaphead
500+ Head-Fier
I mean, it was high enough for sony to push out a version 2 of it. If a company's willing to sink in money to only slightly modify their product and pretty much destroy the market for their previous version, it's abnormally high.
Maybe, but maybe Sony also realised that the MDR-1000X really only pulled level with the QC35, which is the main competition in this market segment, and felt the need for a new model that could pull ahead on marketable features.
I've had the MDR-1000X for around 3 months now, and they're used daily on my commute. They get folded up and unfolded around 4 times a day and still no signs of creaks or cracks in the headband, so I'm guessing that while there may be a problem, it's not as widespread as the internet would have you believe.