I can't speak for the rest of the government, but I can speak for internal whistleblowing of the Marine Corps. You can "request mast" all the way up to the Commandant, which is the tippy top. I think it's possible that some whistleblowing is discarded when it should have been honored, but I think for the most part these processes exist and are in-tact. Now, whether there's a perception that you can use them effectively is another issue.

Let's not forget someone whistleblew on the President amid a highly political environment in recent memory. That's no short order.