Yes - that Adobe model of doing things is bad. Just the same with the old iTunes drmed music files - if you lose your iPod and don't have a backup you lose your music. 

Kindle's model is the only way to go. When you buy through Kindle Amazon becomes your digital library, storing the books for you. Then you can read them on any Kindle device or through a Kindle app on a PC, Mac, phone, whatever. It even picks up where you left off on one device when you move to another. 

No consolation I know for what you've lost already. But a good reason for not doing business with anyone who doesn't back up your purchases for you. I don't think it's a reason to take it out on authors by stealing their work though.