From the Tweet, from Sahil (CEO) himself:
Gumroad, Inc in 2019:
Revenue: $5M (up 46% YOY)
Gross profit: $1.7M (up 68% YOY)
Net profit: $214K
I not familiar enough with the Gumroad model to understand why how the creators made $73M in 2019, but Gumroad revenue was only $5M.