I think that's been the prevailing wind for many years (like 70-80 years). Lots of current and ex employees and relatives treated it like the best and only reasonable investment. Years ago, I ran a 50 year analysis for a client illustrating just how bad of an investment XOM was related to a basic balanced portfolio. She was threatened by an aunt that she would be cut from will if she ever sold any of it. They were in total belief it was responsible for the level of wealth they had. My 50 year illustration highlighted just how wrong they were. I think I used a basic 3 pack of funds from Franklin Templeton.
I think today, not many people are buying it, and many of those that never thought they'd sell are in retirement and liquidating, or growing tired of returns lagging so badly... Hence the decline against an otherwise strong market.
Until the market starts luring more buyers than sellers, this will continue. Bocephus thinks that's anything below $60, we'll see how this plays out.