More devices have HDDs now than ever before; cars, games consoles, set-top boxes etc. As long as HDDs remain cheaper and more economical than SSDs there'll continue to be a huge market for them both in consumer electronics and mass-storage for enterprise.
Personally I think a lot of you are missing a major point.
For majority of uses even 64gb ssd's are more than enough and these are already throw away items, and even 128gb could now be considered that - they are worth pence to manufacturers buying in bulk
So many more issues with mechanical discs in comparison ( power usage, physical size, the mere fact they are mechanical and therefore by definition less reliable)
Everythng by the very nature is becoming cheaper so everything from a mobile phone, to a tablet, to majority of other consumer electronic items are more likely to share as many parts as possible. 18 mnths ago the 128gb iPhone was the largest (easily available) phone on the market - now its already in midrange phones.
Large capacity ssd's are on the way ( to retail) its inevitable as jokster suggested. Its making less and less sense to make larger mechanical disks. By 2020 there will be as large ssds as there are mechanical now (6tb readily available / 8tb if you look a little) in retail - if not ssd's replacement
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People renting datacentre space are highly unlikely to be interested in the "mechanics" of what the servers are comprised of. Primary concern is availability and redundancy etc - not componant technology which will be completely invisible. Is it powerful enough and is it widely available.
Those building their own is another matter, but heat, noise, power and physical size all work massively in ssds favour already
