Iraq was probably genuinely damaging to the US Army's ability to conduct meaningful and realistic training since the lack of fight from the Iraqis gave America a lot of confirmation bias. That might just be pundits though. DOD proper (at least the Army) outside of the academic "wonk"/know-nothing circles seems to be taking Ukraine and Syria very seriously from the perspective of heavy force casualties.
That said, even if it's just a new turret on the same old M1 hull, it'll be fine. The US Army's baby steps around the issue are better than the boondoggle that was FCS, but they could probably move faster I suppose.
A more modern turbine would be nice but the most important thing is to be able to build thousands of them. There are something like 4,500-5,500 M1 tanks of all types (yes, even M1A0 and M1IP with the 105mm) in US inventory and refurbishing even half those old hulls with the new turret would be really nice. This appears to be a classic M1 hull rather than a enlarged TTB style hull so I imagine it's setup for that, since Lima has no capacity for building new hulls.
Since the USA can barely make new tanks from whole cloth to begin with, any major modernizations would need to be put on hold for a long time, like at least a presidential term. It'll take about 4-6 years for the US to build up Lima to capacity to produce triple digits of brand new tanks again (depending on how pessimistic you are) and for the most part they have little capacity for new hulls, but plenty for new turrets, so they can pull old hulls from SIAD and give them the new turret at probably high double digit monthly rates inside 2-4 years. Triple digits would be necessary to build up 2,000 or 2,500 tanks in a decade though.
Since the US and PLAGF have similar quantities of tanks in service, with the PLA being able to very much muscularly out produce America in this regard, the most important thing in a US-PLA fight is being able to isolate a theater. China for the most part has the easier job than America, though, and solving this deficit of military muscle is going to take more than new tanks.
It would take a few decades and substantial reorientation from Japan and Korea back to the United States in global shipbuilding. Unfortunately all heavy industry is being sucked into China right now and there's no sign of this slowing down, because China has what the USA had in 1939: a massive surplus agrarian population. Whether that will hold true in the future is a bit immaterial as both the USA and PRC will be in their median age 40's by 2050 though. China, conversely, won't be as bad as Japan is right now and better off than Germany, Italy, and Spain in terms of median age.
Even then, the ship hull cliff will cut the number of USN carriers, SSNs, and general fleet strength in the early 2040's to "smol". It's why I like to peg Pacific War 2 happening in 2040-2044 or so, because that's when the PLA and USN will be at their relative strength/nadir to each other, and the USA doesn't seem like it's going to be backing down on its imperial responsibilities any time soon.
Which is why the next 20 years is pretty crucial. To have "sufficient" tanks to act as a hedge against ZTZ-25s or -96XYZs, or whatever the PLA will build in the thousands, it's probably important to ditch every last -IP and -A1 at SIAD and replace them with new turrets on refurbished/zero houred hulls. Lima is setup for 150 tanks/month peacetime with 300 tanks/month "M-day", but it's very understaffed and will take years to build up that staff, and that was when it was producing 20 tanks/month and not the present 10-15 tanks/month...
DOD might see that major throughput in the 2030's if it started sometime this year or early next year in training those ballistic welders. They might be able to cut their teeth on export M1 orders and get started on the real deal in the next decade and crank out 1,000-1,500 tanks before the next big one.
Of course there's not much Army DOD can do in this regard because the entire ball is in the USN's court as it stands. A new tank is mostly just going to be a hedge against ground force casualties in a limited intervention, mechanized colonial war like Syria or Ukraine or something where the enemy actually shoots back, but having thousands of tanks to lose instead of a few hundred is pretty important. Russia lost something like 1,500 tanks so far in their frankly limited/mid-intensity excursion, so it's not out of the question in a future Korean War-type conflict, the USA might simply end up running out of tanks after a couple years of action.
