No one needs M1 tanks to maintain order among competing international corporations and the sports-addled sheep they feed off of.
No, but when an unsustainable system collapses - the side with the tanks has typically come out on top.
Today, the US is spending more per household, than the average household earns. Much of that is in Gov't handouts. Now, in my daily workings with the Military, you will find no group of individuals more sworn to the upholding of the US Constitution than anywhere on the planet. They are NOT sworn to uphold Congress - they are sworn to uphold the Constitution of the United States, from enemies both foreign and domestic. They have been asked, and many have laid down their lives in defense of this sacred oath.
If/when the system collapses, and there is a coup; it will not be the bureaucrats in Washington who reign.
There is no love between Washington bureaucrats and the leaders in the military - one could argue that there is a level of tolerance and submission due entirely to a dedication to the US Constitution and the principles for which it stands. Our politicians have abandoned these principles for selfish motives of power and money; but the military remains devoted by a bond of integrity, love and honor that few men that have not served can even begin to grasp. I have not served - as a member of the armed services; but I serve these men in my profession and have not a seconds doubt in placing my life, my fortune and my future in their hands.
The modern battle field still has need of tanks; we are fighting an enemy that lives in caves, who uses commercially available tech to deliver his weaponry. Tanks are not obsolete for the battles we fight today, nor the upcoming battles we will likely face in our lifetimes.