The pollyanna tone certainly makes it seem unbelievable. But editing like this does not help either. Irrevocable???
Yeah, I had to read that sentence a few times to figure out that he meant the *history* of those days is what's irrevocable. The memory would be "irrevocable" if the crime hadn't driven out all of the producers with the memories, leaving the slag who don't remember anything except for the drugs and the great times they had in the '60's burning the place down.
I think the writer was just throwing around $10 words to impress the reader. It's pretty common in the financial media.