I see, was that an M2 memory card? I still use Sony Ericsson phones that are not Android and are Java phones only, so I would now keep in mind to not download apps on it. Sorry to hear about your unusable SD card. I hope you have backed up all the data in there before it got corrupted.
The smaller it is the harder it is to make and besides HDD's have been here for a very long time and as technology ages it gets cheaper and cheaper. SD cards are harder to manufacture therefore more expensive and since HDD's are all over the place now, it's no magic that they're cheaper.
