To get $200 per day, without any interest I'm getting over 16 years of payments... I have to go out to liek a 70 year loan to get down to $200 per day... I don't think that is going to fly. You'll have to replace every drive in the array a dozen times before the first batch is even paid off.
With 6% interest and figuring 36 monthly payments and $200 per drive, I get a cost of $1200 per day.
Now those "4TB" drives probably have an actual formatted capacity of 3.6TB, so you'll actually need more. I come up with 7037 drives. At $200 each, now your payments work out to $1408 per day.
The company that provides the service now, presumably has redundancy-- so you're probably looking at double that. Now were up to $2815 per day.
If the average drive lasts 8 years, you'd have an average of 5 drives failing every day; that is another $1000 per day [assuming the same volume pricing].
Those drives just aren't stacked up on the floor [if they were, just bare drives piled up on a pallet, it'd be over 11' tall], they are presumably in servers, that you have to pay for. And those are in racks. And those servers use a lot of electricity and require a lot of outside cooling and a building to keep them in and employees to monitor and replace drives, insurance, etc.