Your alternatives are 1) Switch to other cloud providers, I'm not aware of any very cheap ones. 2) Switch to other hostings, which can be 1/10 as cheap as AWS

Your alternatives are 1) Switch to other cloud providers, I'm not aware of any very cheap ones. 2) Switch to other hostings, which can be 1/10 as cheap as AWS, but then you have to deal with the failures. 3) Colocate and build your own servers/storage. It's only cheaper if your bill is much more than a 24/7 sysadmin(s) salary. I suspect DropBox don't give a shit about server costs, they are swimming in money. But I bet having their own data centers will save them money.