IMHO it would not have been a morale problem, but a number problem. The army was already downsizing a lot of units were paper formations (there was a reason why it was called the Hollow Army) yet the morale was good. Tow thing have to be kept in mind. By end of 1971 US troops had a very limited combat role so experience would have been quite limited anyway. At large the bulk of the combat forces in vietnam were volunteers and they kept a good morale until the end. There were indeed morale issues(some very serious) in several units in Vietnam but usually they were confined to non combat units. Combat units tended to weed troublemakers very quickly. To a certain extent formations in Europe were filled with draftees to allow regulars to serve in Vietnam, yet a lot of these regulars were returning.
An even bigger problem would have been logistics. Without reserve and NG call ups the bulk of the regular US Army logistic units had to be used to keep MACV operational. Severla logistic units had to be created from scratch. OF course these were quickly disbanded but… their equipment was siphoned off from Guard units and other regular units and suffered attrition and overuse. A lot of motor transpoert, POL, supply and maintenance companies were stripped bare of vehicles by 1973.
Another factor was that the Army was behind of one equipment cycle. No M60A3 TTS or fan cy tanks, the bulk of the combat force was vanilla M60 and A1. Very few A2. No M48A4 or A5 with 105mm gun.
What the US army in 1973 had was a lot of battalion/brigade/division high intensity experience. Unit staff knew how to operate, they knew real supply allocation for combat units. Even if combat in Vietnam was different from Central Europe they had accumulated quite a lot of experience in useful skills. They had also battle tested SOP. They had still an higher degree of internal cohesion than few years later (the real nadir of USAEUR was 1978-79 that period was scary).
On the other side the soviets had yet to amass combat experience in Afghanistan… It is an interesting period. Now we need the M60… and the M48…
Also the Motor Rifles and the BMP1s are perfectly useable for the following decade…
ponders nirvana.
