Yes, I completely agree with all that and, having seen 'how they work' (as you describe), I'm pretty surprised that they last as well as they do!I have had one light switch fail here in a slightly longer period and I agree, they rarely do fail, but they are wall switches. Ceiling light switches fail rather more often, they are maybe more complex/ more delicate and abused more - yanked by the strength of an arm, rather than a finger tip. An additional problem is the current the have to carry, even if they don't switch it - up to 45amp, in what is a fairly compact space. They also use a similar mechanism to many ballpoint pens, to convert a pull into on on/off. The mechanism of lots of these pens fail.
I have a few (light/fan) pull switches here and I can't recall one failing the the 30+ years. In particular, we have one in our downstairs loo which is still going strong after all those years. It has no windows (so light is essential for every use) and it is more-or-less the only loo which is used 'during waking hours' by all of the occupants and any visitors - so goodness knows how many operations it has experienced in all these years.
I have to say that I don't recall many complaints of them failing 'mechanically' - the issue usually seems to be overheating of terminals/connections (usually the neutral conductor!), but maybe my memory is failing me.There are also lots of complaints of shower pull switches failing in this forum.
Kind Regards, John