.The fuel theory is most likely a total red herring, expecially in view of the reported electrical problems.
Too early to say of course.
But there have been a number of high profile accidents in the past where the crew focussed on a (minor) technical issue and forgot properly monitoring fuel or speed.
Next to that accidents happen when multiple things go wrong. It is a series of events and not (as far as i have seen - never) a single cause.