That graph is average paid in USD per transaction. A transaction from an exchange with 300 inputs and 500 outputs is going to be paying a magnitude or 2 more than a simple 1 input 2 output transaction. But in your graph they are all lumped and averaged together.

It's like me saying "The cost of electricity is lower than ever" then you show a graph showing the average electricity bill is $800, but don't include the information that it includes the aluminum forge down the street...

The correct graph to look for is "satoshi per byte that will get you into the next transaction". And while i'm sure you can find dates and times in the past year where it's been technically cheaper, the reality is that right now it's about as cheap as you can get to transact in bitcoin (5 sat/byte fees are going in the next block currently, it generally doesn't go much lower because many miners won't include fees below that). That hasn't reliably happened since early 2017.