Samsung is South Korean, a US ally and SIGINT partner. Modify the argument to, "the government is saying not to use any phones that are not from the US or its puppet states."
Nope, per recent incidents.
I'd say that is a LOT of influence.
But, do they feel above the law? This is certainly a common complaint of South Koreans. These groups are definitely "too big to fail" and they know it. So yes the concentration of power in a few giant firms is remarkable, and not in a good way.