With the cost of storage being what it is I seriously question any business model that tries to sell you a plan based on the size of the storage on the other end of a wire.
You're basically setting yourself up to have a 'gmail' pulled on your 'hotmail'.
Why not extract value before that happens? There is always going to be the risk of a new competitor operating below costs, but money in the bank is the best way to fight that.
PS: Nobody things the best way to beat gmail is to offer 1 TB email accounts. Email fell behind the HW curve but as long as Dropbox stays reasonably close to actual costs nobody is going to dramatically undercut them.
You're basically setting yourself up to have a 'gmail' pulled on your 'hotmail'.