DRAM shouldn't really fail within its life expectancy anyway. If it does, it's going to be because of an original manufacturers defect, and not likely from wear and tear. Flash RAM is the exact opposite though and I really think that's a shame. They need to make flash storage more reliable. As it stands, with flash RAM having a baked-in limited lifecycle, an SSD is not really any more reliable than a hard drive with a spinning motor (actually 2, if you count the motor for the arm). The difference is mostly in performance, but the value proposition is pretty weak when you factor in the price. Now if there were a way to use massive amounts of cache with a hard drive, and use DRAM instead of flash RAM (which they already do now), hard drives could easily get up to speed. It doesn't need to be a huge amount of DRAM either. I would say that 1GB of DRAM with predictive drive search algorithms would push hard drive speeds well into the performance realm of SSD's, but with a more manageable cost. TurboMemory didn't work because of the relatively low speed of flash RAM. I think that was a mistake using flash RAM.
Here's what I'd like to see for desktop drives:
a) A 2.5" form factor drive platter size with a 7200RPM rotational speed (probably required for space of battery component, unless a hardware manufacturer can squeeze a small battery in)
b) at least 1GB of fast DRAM (DDR2/3/XDR, etc.)
c) battery backup to flush the DRAM buffer on power loss
d) SATA 6Gbps interface