That hasn't been demonstrated. It could be that when the decision was made to offer free/unlimited storage, there were beliefs about the economics of that option -- particularly, the rate of change in durable storage pricing and performance -- that ended up not being borne out. (I am not privy to any special knowledge about this, but it is at least plausible based on how the storage business had been working for the years leading up to 2015.)

I agree in general that teaser rates -- as opposed to well documented free tiers -- are at best a gray area.