I would rather Mobil stops producing M1 until the supplies improves than for them to do behind the scene reformulating and pretending everything is fine. This seems to be an easy way to destroy the value of a premium brand. People buy a premium brand because of the confidence and consistency they expect from it. If people start to lose that, the value of the brand will be fleeting.
Personally I would reevaluating my options once my current stock of M1EP are gone in a year. I will have to wait to see the data saying their latest formulation is still good before I will buy it again.