Steem has a higher inflation rate than the USD, depending on how the USD inflation rate is measured, so it may be inevitable for it to drop over time even compared to USD, which makes it quite a bad buy.
Steemit suffers from many problems, which are detailed in my past threads and comments.
Its high inflation rate, no fees, etc. are only part of its problem.
Value can not be created out of nothing, and even the average content here is quite bad, mind you all the "color challenge"s, etc.