^
Yes, I knew. I experienced all of this first hand, in chronological order as it happened. Revolver was the first hint as to what was happening. I was just sixteen at the time. With Sgt. Pepper's we continued to see their different and distinct musical styles. The White Album expounded on this. Yes, we knew something was happening but we just weren't sure what it was. We wanted to think of them as a band that would take us into the 1970s and beyond. After all, they were young and reaching the peak of their creativity. Thanks to Ed Sullivan and David Frost, we got to see them on TV with their Paperback Writer, Rain, Hello Goodbye, and Hey Jude videos. They certainly looked cohesive enough. We had Magical Mystery Tour and Yellow Submarine movies to reassure us that the band was still viable. Without the internet and Beatles forums such as this, we had to rely on the news and fan magazines to know what was going on.
In the fall of 1969, we got Abbey Road and for a while we thought everything was okay. A great LP with a magnificent closing medley! And we just knew they would be around in the following decade.
A pivotal moment for me came in late January 1970. Come And Get It was playing on my car radio, an MGB which added to the British atmosphere. I turned to my girlfriend Nancy (yes, I jokingly called her Magill and Lil at times) and said "Listen! That's a new Beatles song!" It sure sounded like them. When the disc jockey said it was Badfinger, we both exclaimed "Who are they?!"
And then came the Let It Be movie and LP. We knew it was over even with the short exchange between George and Paul..."I'll play it your way...or I won't play it at all."
I apologize for the extended prose, but I hope I answered your question "Did any of you know?"