As to the rth not working, I cannot say. I have never used it, nor do I want to. I would rather be in control and flying by numbers than let it fly itself home.
Nobody wants to use an airbag either, and it may not even save your life. But I sure as heck want it to work when needed. I pay attention to my RTH settings, and test it to make sure it works as expected.
If the OP's RTH button really didn't initiate RTM after a long-press, I would advise testing it in a controlled setting to see if it is an issue with the RC. (My gut feeling is that it does work but in the heat of the moment it was not long-pressed.)
Mike