As a data storage it has already lost to even memory sticks,
http://aufoav.en.made-in-china.com/offer/RqJmjYToqLkP/Sell-16GB-32GB-64GB-128GB-Kingston-Mini-Fun-USB-Flash-Drive-Pen-Drive-Memory-Stick.html
(Theres sticks up to 128GB.)
And when it comes to fist size usb hard drives, they already can have capacity of 1TB or even more.
http://tech2.in.com/india/news/portable/wd-launches-2-portable-usb-hard-drives/79782/0
And I think games will be downloadable in the future. Actually its in some cases already faster than buying physical copy. :)







