Re: The price is astronomical, but..
It does look like the writing's on the wall for spinning disk, but it's been that way for a long time. The amount of data being stored is increasing at the rate the price is coming down, but that's the same no matter what medium is used for storage. It's the total cost that matters; not just the cost of the device itself, but all of the other stuff: power, cooling, rack space, reliability etc. And it's a different calculation for different applications; even in the enterprise, few applications actually need the performance offered by SSDs, which is why data centres are not wall-to-wall flash. If there reaches a point where flash is at the same price point overall as rust, then the switchover is inevitable, but it's not going to happen much before.
If you sweat your assets for 3-4 years and are buying now, I reckon in two generations it will be all solid-state. Right now, if you have mixed workloads (as most people do) then hybrid's the way to go, at least in the enterprise.