Flyback version of the Saturn rocket

When I saw this, I was surprised, to say the least.  Something that I've written about here several times, was actually considered during the Apollo Era.   A bit reassuring that, even though the idea wasn't mine, that it could be feasible after all.  If flyback version of the Saturn first stage is feasible, surely a smaller version is just as feasible, if not more.

Here are other links to more information on the proposition.  A picture down below:

Flyable rocket, first stage of the Saturn rocket in the Apollo Era

 More pics below:

The above schematics were of an early Shuttle concept using Saturn V rocketry.  The Saturn V was discontinued.  It looks like this design may have given a faster turnaround than the SRB's, because of the ability to flyback, and to be refueled quickly.