I know exactly what you mean. I'm currently writing a very time intensive novel and publishing it chapter by chapter here on steemit.
As rewards go down, I'm finding less and less energy to put towards that novel.
However, I have always believed that consistency is key. I have a certain reader base that want to read the novel and it's not fair to them or even to myself to stop writing or slow down JUST because rewards are lower.
Sometimes it can definitely be tough especially when it seems like things aren't going your way. Still I've written every single day for about a year or more and I intend to continue despite these feelings.