This is a badly flawed study, since you claim to be a engineer, you should recognize that.
Oooh, that comes across as quite catty, especially when you say "claim to be".
There is no testing, just info from random people...
Random would be great but these people are not random!
...with failed shutters
The vast majority had working shutters.
a data point of 1 or 2 is less than useful.
There were over a thousand data points.
The major, overwhelming, flaw in this study is that it uses a self-selecting sample, can't believe you missed that!
To the OP: Hadn't given it much thought before, always assuming the lower the shutter count the better, but finding where the bathtub curve 'bottoms out' makes great sense. Thanks for the analysis, however flawed the source data. Pity you had Mr Negative try to kill the thread before it started :-/