If this was indeed MCAS, it is my understanding they 'could have' stopped this by turning off power to the electronic stabilizer trim.
I find it embarrassing for the society as whole how many people these days comment on articles or posts by just reading the title.
I think that what they would have needed was an intermediate mode, "disable the decisionmaking, but keep the power-assist". But that would only make the checklists even more complicated, at the cost of valuable time and more possibilities for user error.
"The crew performed all the procedures repeatedly [that were] provided by the manufacturer but were not able to control the aircraft."
Does not match MCAS as it has been explained to me.