I don't see that at all. Their last two albums, Let It Be and Abbey Road , were both really good. Given the immediate successes of the individual careers of Paul, George, and Ringo, it didn't look like the Beatles were slowing down much. It could be argued that McCartney and Wings became the biggest act in the world once the Beatles broke up.
It was clear that the personal relationships were strained (particularly between Paul and John) but if they had acted like professionals and set aside those differences, they still had a lot of creative ideas. It was also clear that the world had not tired of the Beatles yet.
More that times were changing as the 70s came in. That’s not necessarily a comment on the quality of the music. But seven years is a pretty good run, all the same.