Will's PDGA earnings the last 5 years:
2012: 39k 38 tournaments played.
2013: 34k 35 tournaments played.
2014: 28k 34 tournaments played.
2015: 32k 30 tournaments played.
2016: 16k 31 tournaments played.
His number of tournaments in the past didn't change drastically but his earnings (and his rating) took a dive in 2016. Granted his personal life changed forever when he got married in 2016, so I'm sure that factored into his mental state on and off the course. He has played in 3 tournaments this year and only has 5 more in the books so far. Maybe he's at a point where quality > quantity.
Perhaps things have stabled out a bit for Will now. After 2017 is in the books, we'll have actual evidence to conclude if Will has indeed peaked or not.