Right now, I'd imagine Unity is more concerned about placating their investors that the company isn't going to fall off a revenue cliff.

Appointing a "developer-friendly" candidate would have caused more uncertainty.

As a temporary pick, I'd guess Whitehurst is intended to message "We realize we screwed up, but there won't be any sudden changes."

The reaffirmed guidance for current quarter is hilarious though, given any changes would play out in future time (e.g. developer flight for next project).