That “source” is some NASA tutorial that just states that quote without any elaboration at the bottom. I don’t know how that passes as a source at all nor is it generally applicable in modern ships.

On the other hand there are multiple ships currently using these as additional propulsion system (as you can see further below in the wiki article). Flettners inital prototype used rotors as exclusive propulsion system. One could also use a kite or a sail by using the wind in favourable conditions.

If you wanna be serious about saving fuel use Flettner rotors.

The process described in OP’s text is what I consider as recuperation, the conversion of a radical idea to a commercially viable one by de-radicalising and twisting its foundational ideas, which then enables commodification. A radical idea needs softening first before it can be turned into a commodity (like your example of Che tshirts). But your point is still valid.

https://en.wikipedia.org/wiki/Recuperation_(politics)