But what was it that caused the USMC to shift? I've read it was, among other things, the increasing cost of upgrading the M1 as a fighting platform, when viable alternatives existed, this the pivot away from tanks. As a tank fan, I favour the MBT in the inventory.
It was a desire to re-focus/re-align the mission focus not a cost cutting measure. Basically the US Army has the tanks and the role of the USMC was not to be just a maritime version of the Army. See the following for some of the thinking:
Commandant Gen. David H. Berger has said that should armor be needed by Marines, he would look to the Army to provide that capability.
www.marinecorpstimes.com
Except the US Army also has three divisions of paratroopers who have better rapid response times than than the Marines?
Berger's transformation of the Corps is shifting it from a ground fighting force to glorified coastal artillery. It looks like mirror imaging in a sense, except Naval Strike Missile and PrSM are a bit less than the Army is offering in the "A2/AD" role, on top of not being very good at fighting in traditional Marine forcible entry operations since future Marines are lacking a third to a half of their airlift and JSFs.
The "maritime Army" of a mechanized Corps would actually provide COCOMs with some measure of meaningful heavy armor in the first two weeks of combat, which is something the Marines have proven to provide faster than the Army in Desert Shield and Urgent Fury by beating the Army to the punch of tanks on the ground by a solid four or five days with on-station MAGTFs and MPF ships.
It really does seem to be a rather slash and burn budget cutting measure rather than any force-oriented objective.
There's no real mission set that requires the Marines to sit on shoals manning short range rocket batteries though. At least not that doesn't have Congress questioning why we even have the Marines, if the paratroopers can do that job cheaper and faster with HIMARS and MMRM.
I think Berger's just playing the long game and hoping LRPF is done competently enough the Army will get to pay for new M1s, which the Marines will happily buy once, only they've eaten the massive bitter budget pill that is JSF and H-53K, and those ships' unit costs go down. Seems to be between ACV, JSF, H-53K, and whatever Cottonmouth is going to be, as well as the weird shipborne UAS the Marines waffle on to replace the old Broncos, well the M1s can get sidelined for now, along with a third of the aviation fleet, and all that can probably come back in 15 years or however long it will take to regenerate.
Maybe they'll buy MPF though if that doesn't get killed.