i've seen many ssd's die in enterprise SAN kit and will even go so far as to say as a percentage they die far more often then spinning rusty metal.
However, this is because of how they are used in SAN. Often they are used in a multi-tier way, where most frequently accessed data is pushed up to the SSD's to allow quick access, so they get hit the hardest.
I would be guessing your asking this question simply cause its easier to understand why a part-in-motion can slowly die over time where something thats in silicon shouldnt. You'd probably be surprised to know that alot of drives die a controller death, not a platter/motor death. Typically a platter/motor death usually means a badly made drive (mostly because makers of spinning rusty metal have gotten very good at the mechanics behind them) and while the mechanics in a drive will slowly wear over time, typically something silicon in the controller goes first. The exception to that is where drivers are physically in motion not of their own (i.e. laptops for example), often then the drive shaft in the drive itself starts to get wear unevenly and that usually gets worse over time (or at least, this is what i've been told).
Some SAN makers will even put hdd's through their paces first to make sure they actually perform ok - for eg, they'll measure vibration, etc (i.e. the mechanical components) to make sure a drive is up to spec before it goes into their kit - they cant really do the same as easily with silicon as theres not much to work off that can be measured - so often in enterprise grade SAN's, silicon dies before mechanical.
http://www.makeuseof.com/tag/solidstate-drives-work-makeuseof-explains/ is a fairly good explanation of why ssd's die (and relavent).
Having said all that, i honestly cant wait for the death of spinning rusty metal for the simple reason that ssds should (and havent yet) taken on forms which would be much more useful - why use a sata 2.5" format when you could have much better geometries for example? Then theres the interfaces we use where were really designed with hard drives in mind... but thats an entirely different issue.
As for "if its all the same, why doesnt it die at the same time?"... because at a fundamental level, it isnt the same. When we make anything no matter what it is it, the materials go thru some form of refining process where impurities are removed. Its impractical and near impossible to get anything 100% pure (not to mention entirely uneconomical - you might pay $1/tonne for 90% pure iron and $100/tonne for 91% pure iron as an example). The nature of where we get those materials often means the impurities vary greatly in composition in small spaces of time, hence why two hdd's sitting next to each other on the assembly line might mean one will die after 2 days and the other will die after 200 years. Theres also other components to this in that if you looked at iron (again an example, but true of most metals) under a microscope you'd find that it isnt a uniform substance, its quite grainy so to speak and those grains vary considerably. This too impacts the nature of the substance and its longevity. Using iron as an example, when its cooled its very hard to get a truly consistent cooling of it across the entire piece and the cooling determines how those grains form - i.e. grains in the center of the material will be quite different to grains at the edge and so forth. Thats just a small number of things that explain why consistency isnt quite as 100% as it might appear to be on the surface, there are quite alot of factors that come together to effect materials we use. Ultimately the way we choose the materials we produce things with is by tolerance, i.e. i expect 99% of my metal you sell me to fall into 90% pure and have x tensile strength or any number of variables you might consider important to your manufacturing process but even then its never 100%, you always except at some point that you'll get raw materials that'll fall outside those tolerances and as with everything on the planet its a trade off between price vs quality!
