The the war becomes even more of a logistical war, hunting reloaders and refuellers.
The M60 isn’t really big enough and there are internal structural issues; the thing about the Chinese tanks is that they incorporated the Soviet Bloc idea of the ubiquitous autoloader - i.e., there is no human loader in the tank, there is no provision for a human loader in the tank and if you lock down the firing switch and then bail out of the tank, the *stock* tank will actually fire and reload itself until the ammo runs out. They also have semi-automatic targeting, again imported from the Russians; Russian tank protection systems can actually slew *and lead* the gun onto targets detected by their APS sensor pack - including attack helicopters and slow moving attack aircraft - to the point where the gunner or track commander need only confirm the engagement for the tank to fire on the target all by itself. Adding remote gunnery and driving controls to a vehicle that already does that is quite a lot easier than trying to adapt an mostly-manual track like the M-60. The M1 is also a mostly-manual tank as are most NATO tanks - NATO’s dogged insistence that Active Protection Systems and automated threat detection/targeting wasn’t needed (driven in part by a belief that Russian missiles were not effective) has come back to bite in more ways than one because the recent fights in Syria where Konkurs missiles demonstrably took out reportedly Chobham-equivalent-armored ex-German Army Leopard 2A5s like they were made of tissue paper has shown that this NATO common wisdom was incredibly wrong. The US Army is now hastily re-equipping with Israel’s Trophy APS, but the M1 will not be able to gain the Israeli Merkava’s or the Russian/Chinese tanks’ ability to automatically target and counterbattery threats detected by the APS for quite some time.
Another issue with converting an M-60 is the minor little problem that we don’t actually have any any more. There are no longer any M48, M60, or M103-series tanks in the US inventory other than as ‘gate guards’ or other such monuments or museum pieces - all units, parts and such were either sold to foreign countries or scrapped.