This is where the bubble lies. 1TB of raw data storage costs ~$90 these days without power, maintenance, installation, support, data transfer, failover/redundancy/backup... over 3-5 years (the usable life of these drives) at current market prices, you should probably calculate close to $1500 to store and maintain 1TB of data that is properly backed up, redundant and available.
The current cloud providers (Microsoft included) are counting on you NOT using your storage beyond 5-10%. Once everybody starts using more than 15% of their allotted storage (which is inevitable given the increasing amount and sizes of stuff we store) someone will have to pay up.
I do maintain the in-house storage where I work. Even at the lowest market prices and the volume we have (currently ~200TB of usable storage), we are this year looking at a cost of ~$200-300/TB investment just in bare hardware and those prices really haven't dropped over the last 5 years because even though raw storage has dropped somewhat, the hardware to support them has not, replacements for failed disks need to come out of that budget and we need ever more and faster interconnects (larger RAM caches, larger SSD caches, faster SSDs, gigabit to 10g upgrades, SAS interconnects from 3Gbps to 12Gbps) to maintain equally speedy access to all parts of the storage for an increasingly growing and demanding user base.