Their swansong “Abbey Road” was their best, and the best album ever. They wanted to go out with a flourish, and they did. They wanted to go out on top and they did. Every album from Revolver to Abbey Road was a masterpiece, but Abbey Road has always been my personal favorite. If I had a buck for every time I’ve listened to it, I am sure I’d be $5000 richer.
I do think The Beatles broke up at precisely the right time, they had nowhere to go but down from there, and judging from the solo output from the 70s, it wouldn’t have been good.