I just saw the excellent documentary "Stones and Brian Jones" which really captured a lot of the electric volatility of the '60's. Some great B&W concert footage reminded me of just how berserk & hormonally out of control these early '60's concerts really were; teenagers just absolutely hysterical, near RIOTS just amped up by the music & their own temporary insanity. "We don't KNOW what we want, but we want it NOW!!!"
Brian was ESSENTIAL to the band but yeah, they had to get rid of him. His musical contribution by 1969 had dwindled to nothing, and even by Keith Richards standards, Brian was a hopeless drug casualty. A surviving girlfriend spoke of how Brian would be drinking coke & whiskey all day long along with all the weed & pills. He was a disaster waiting to happen.
Even so, I lost interest in the Stones once Brian was gone. After decades of hearing the raves about "Exile on Main Street," I bought a copy, and let's just say that I'm not feeling it. "Let it Bleed" was their last great album for me; as always, no one's "wrong" to have stuck with them since 1969, but that's where I draw the line.
