The sexual revolution was enabled by two things:

1. The invention of "miracle drugs", the antibiotics that took the terror out of syphilis and the other VDs and

2. The passing of the last of the Victorian-era people.

I think the supposed prudishness of the Victorian age itself was a response to the spread of syphilis moreso than any character (or lack thereof) of the reigning monarch.

And even so, the so-called "liberated" women of the 1920s - the flappers, like my grandmother - did what the men were always supposed to do, too - stop with the drinking, smoking and carousing once they "settled down" and had kids. But the subversives started saying that no one should have to give anything up for the few years it takes to raise a few kids and boot 'em out of the house ...