Arcadian

I will also say; I think Iron Fist was the most disposable show for Netflix, if they had to drop one of them. Daredevil essentially already brings whatever elements Iron Fist provides for the audience, Luke Cage & Jessica Jones are attractive properties for obvious reasons, and Punisher is its own unique thing as well. Iron Fist just hasn't provided anything new or unique, its only brought on controversy left right and centre (to no fault of the property, just the show, but still).

Netflix invested a specific budget across all the shows. I think they really did want to see if they could make a better season of Iron Fist... and they did I guess, but not to what they were hoping for. The reviews were still lukewarm and as was mentioned above, they have their own ratings/viewing system (which they don't share with the public), and from the looks of it, it must have been bad. But yeah, its a mixture of elements.

They probably don't want to bother wasting their budget on the show anymore.