All drives are prototypes!
Every drive you buy today is a prototype, in that it has not been tested for as long as you hope it will last. They do accelerated ageing tests (run them hot, or alternately too hot and too cold, shake them, power them up and down every ten minutes ...), but that cannot fully substitute for the passage of several real years. By the time you and the manufacturer know it's reliable, it's also obsolete.
I had a batch of PCs with same-batch Samsung Spinpoint drives. After three of those drives turned into bricks at power-up, with no prior warning signs from SMART, I replaced the other four pre-emptively. I don't hold this against Samsung, because I have experienced or heard of bad-batch problems with every other make of hard drives. However, it was my first brush with sudden-brick failure. All my previous failures in the SMART era either gave advance warning through SMART, or were recoverable using ddrescue.