What do I care about people leaving Bitcoin including someone named Mike Hearn even though I found out from a google search that Mike Hearn is a former Bitcoin developer.
He left Bitcoin probably because his thinking has changed due to something that is not certain what the main reason is.
Why do I say what do I care, because Bitcoin will continue to run as time goes by.

Then regarding your feeling that Bitcoin is now chasing fiat profits. I am silent because I have never felt that way at all even though I cannot use Bitcoin like fiat to pay for goods and services.