Four Corners has had bus service since the 1940's, years before the formation of WMATA (Metro) and a long time before Montgomery County created Ride On. The service was originally run by D.C. Transit (formerly the Capital Transit Company), the private frim which ran the buses and streetcars in DC and the Maryland suburbs from 1933 to 1973 (Metro was formed in 1967 but D.C. Transit was not eliminated until 1973).
Below is an inset map depicting routes in the Silver Spring area as of March, 1958.
Unfortunately, service like this ceased to exist with the opening of Metro, when most bus routes became feeder routes for the new rail stations. Today, there is no "one seat ride" from Four Corners to downtown D.C. because of the realignment of bus routes to serve Metro stations.
However, I think it would super convenient if the S7 and S9 still existed, given the unreliability of the Red Line (well, the S9 actually does exist now, but I'm talking about the old alignment). On weekends, when Metro is incapable of operating effectively due to two decades of deferred maintenance, I really wish there was a bus route from Four Corners straight to downtown DC . Having buses which normally terminate at suburban Metro stations continue downtown on weekends could make up for the notoriously inefficient Metro service. Maybe we should look to our past bus network to solve some of our current problems...
To learn more about transit history in and around D.C., I highly recommend visiting the National Capital Trolley Car Museum. They have a ton of resources (such as this map) and some really committed volunteers who preserve this stuff so the rest of us can learn from it.