So, you watched them bake a cake without Julia Child's doing the dialog. Sorry it was boring. Although the cake was really good.
To take them as peaking at a point or whatever, I can't go there. To me they were always evolving. Their ability at convergence was second to none. They layered solo's better than anyone. Their vocals, unbelievable. Individual ability, I don't think any of them could read music but they all contributed beyond so many others. Look at some of Ringo's solos (microphone is a suitcase), Paul's bass on Sun King, George was as good or better than any lead guitar, I loved the sitar and the desire to go beyond a standard western beat and John's poetry was on par with Morrison, Keats, Byrne or Lewis Carroll (Jabberwocky a personal favorite).
At the end there was divergence. That divergence was its own and I love it. Everyone wanted them back together. That could only happen as their evolution allowed. Free as a bird, to me was like watching grand great elephants coming in to mourn the loss of one of their great ones. We had some convergence, it was nice.
Now, lets talk about some "other" bands. Did their sound evolve? The Beach Boys, perhaps. The Stones, nope. Bruce, nope. Name another band that evolved as much. I have to go to Dave Brubeck and his differing time signatures.
In summary I am thankful for the Beatles and all they did. They had an alien probe up them 24/7. This was a picture into their daily in a bakery making bread. It's okay. I would love to see this for Beethoven, but I guess that's not possible.
Me, I would prefer to just enjoy and not worry too much about an extra added whatever. Be happy, peace and love.