It's a funny thing because back when the fees were crazy high the number of transactions was much higher. One might think that the cheaper it is to pay the more people will do it, guess not
I think the transactions fell because a lot of new people who went in because they heard that you can make a lot of money fast with Bitcoin lost money and got scared, while long time holders don't want to spend their coins because they see the potential. The prices are too low to waste coins on gadgets when they can be worth 20% more in a few weeks.