No, you're off the trot there. People are still gathering there because we still live in an agricultural society. I know everyone disagrees with this - information age (etc) but our lives still revolve around producing and consuming food. The test, of course, is to go without for a few days.
Have a look - ie Google - the stone watermill at Little Salkeld in Cumbria. Nick, there, is a particularly helpful individual (if he's still there) and it would be useful to run your theory past him. (He's been producing lovely flour for thirty years).
In a strange way I have sympathy with your view - I believe the potter's wheel was in use here long before it is accepted that it was - but there is little or no supporting evidence. What we have - querns and worn down teeth - suggests that milling grain was a kitchen enterprise. And I've done it - remember the old Corona mill? No wind power neede there, just a sturdy table and some elbow grease ...
exactly, querns and worn down teeth. neolithic saddle querns were most often made of very hard sandstone sarsen. odd don't you think that granary at stonehenge was made from the same.
here's another test to see if the ancient people ate grain ground on sarsen stone. perhaps there is some specific trace of sarsen minerals in those very same ground down teeth.