Steemit has been around since late spring of 2016 and has seen constant, steady growth in that time.
As the digital currency exchanges fluctuate all the time, the amount of money you can objectively earn from Steemit will depend on market conditions. a single Steem has been valued as high as $4 and as low as $0.09; at the time of this writing, Steem is valued at about $3.77 and is rising.