The Rolling Stones at their most radical?

I'm reading "THE ROUGH GUIDE TO THE ROLLING STONES" this week and listening to the band's albums in order.
Yesterday, I reached "BEGGARS BANQUET," the 1968 album I now consider to be the Rolling Stones' most radical work -- when compared to its predecessors.
Songs such as "No Expectations," "Jig-Saw Puzzle," "Prodigal Son" and "Salt of the Earth" sound like they come from a completely different band than the group that create such albums as "Aftermath," "Between the Buttons" and "Their Satanic Majesties Request."
Is that because co-founder and multi-instrumentalist BRIAN JONES had largely faded from the scene, mere months before his sacking and death? Was KEITH RICHARDS exerting more control over the band as a result?
No matter the reason, "Beggars Banquet" marks a complete departure from the band's previous musical trajectory.
One of the great fallacies among some Stones aficionados is that "Beggars Banquet" represents a return to the band's country-blues roots. What country-blues roots? The songs from the first clutch of albums in the band's catalog are covers of Chess Records-style R&B -- much more B.B. King than Robert Johnson.
If The Rolling Stones had country-blues roots, they kept them to themselves and didn't record them.
While "Beggars Banquet" marks such a clean break, it also represents a template that the band would loyally adhere to, even to this day. Styles like funk, disco and even reggae were later incorporated into a swaggering, bluesy sound that got its start on "Beggars Banquet" -- an album that's radical and trend-setting.