No its not. M60 tank performed very well in the gulf war. It was a lot more mobile than the Abrams. The US forces would have performed a lot better if they had only used M60s. Its cheaper, lighter, easier to ship around the globe, and has a more reliable engine. Just because Abrams has some go-go gadgets, most of which can be backfitted into M60 and other even older tanks, doesn't mean that Abrams as an overall system is superior to M60.
M48 is another story, it is a rather old tank. But I really doubt that the 75 ton Abrams could have had the same effect in Vietnam. The Abrams doesn't even have a proper anti-personnel round to clear those bushes from Vietcong.