I think what you said is also true because buying MASS at a very cheap price at this time will be more profitable than mining and waiting a long time to collect before selling everything into the market because mining takes a lot of time, while buying only takes time to upgrade price in the market.
How can you say buying from exchange is more profitable then mining this? There is no data available here that shows how much HDD it takes to mine certain amount of MASS. Mining is different strategy and you cant mix that with buying a coin from exchange. They two are entirely different things.